Here's a collection of ill-formed ideas of mine, maybe it will inspire someone to flesh them out or do something useful.
General philosophy statement: I don't think the customary ban on PvE-only skills makes sense anymore. With the pve/p split anet have thrown balance out the window and there are a number of completely overpowered "regular" skills now, and those need to be considered too when one feels motivated to ban PvE skills. There's also a bunch of EotN skills that aren't that strong which could be a fun source of variety. E.G. the reasoning behind ele variant encouraged various support and elemental pve skills, while banning the absurd damage ones like pain inverter, finish him, even technobabble.
On the other hand I'd still keep consumeables banned by default unless you're going to do the legwork to integrate them properly. This is mostly because it feels lame that some money can get you past a hard part, but at the same time if you balanced your variant around consets used constantly, it would get pretty expensive. The DP-reducers aren't necessarily so objectionable, but things like celerity, or a tank stacking +100 HP bonuses are. Against everything I just said, there is the point that consumeables could be a safety valve against getting stuck on one particular mission.
Beyond Nudists
Concept: use "cursed" items, a form of nudists that heroes can play
Rules: wear full armor, but must use 5 superior attribute runes. Casters must use a "high set" at all times (+15 energy/-1 regen wand and focus). Possibly ban all % health damage reducers (shelter, prot spirit, etc.) DP-reducers/morale boost consumeables allowed.
Issues: Not sure how to handle physical attacks or ritualist items. There are drawbacks on physical weapons but they are really minor, and it's not necessarily fair that dervish/sins get 4 pips. Could boil down to an imbagon keeping people alive (it could still be difficult in hard mode, but EVERYTHING would depend on the imba...) at the same time, not sure a blanket ban on PvE skills is good.
Monster masquerade
Concept: attempt (and fail) to infiltrate/spy on monsters; a simple way of playing monster skillbars, and get the feeling you beat enemies using their bars but with superior tactics.
Rules: your skillbar must come from one of the monster types in whatever area/mission/dungeon you are attempting. Each player must choose a different monster type, and it must be a regular monster in the zone (not boss-only). To that bar, players may add a rez (signet or within monster class), the starter heal from their monster's class (heal sig for warrior, orison from monk, etc.), and a "secret weapon" (skill from outside the monster's class - possibly pve) Additionaly you must wear a holiday helm (preferably one that looks the part.)
Issues: a real mess with the advanced EotN double-profession monsters... should be some compensation vs monster-only skills too like PvE skills in their place.... healing is also very limited in most monster groups... and I dunno if people like having such fixed bars.
Barbarians Redux
Concept: way simpler implementation of BAR that is just a tweak on Samurai; mostly ends up as yellow-way
Rules: no spells, binding rituals, or forms; only norn PvE skills (BARs not trusting of other outsiders) - must use all white gear (white weapons, no insignias or runes)
Issues: it's alot of effort/inventory to set up characters for all white, but has a fairly minor gameplay effect in GW. Most touch skills are questionable (vampiric bite), but some aren't (shove/grapple) and alot of them are bad anyway. Signet mesmers are likewise questionable, but dolyak/heal sig fit perfect. Very reliant on at least two paragons to keep people alive with synergizing shouts, which could be an issue for large human teams. Completely uninviting to casters.
Undead Legion
Concept: in many systems (like D&D), heal spells actually HARM undead... so healing is very limited here. Mostly an excuse to play a low-healing variant.
Rules: Healing skills are banned, with these exceptions: life-stealing, health gained when damage done (vamprism), regen (undead are known for their resiliance!), life transfer (infuse health, or stealing from spirits) resurrection (brings you back with x% health) Must wear a holiday headpiece that looks the part (zombie mask, maybe demon mask)
Issues: this really is quite insane... people will end up as death nova sac outlets to generate minions, and be brought back instantly with unyielding aura... again risk of becoming overly SY-dependent, although minion/spirit walls are a good solution and very in-flavor.
Completely Overpowered
Concept: focus exclusively on "overpowered" skills that "take all the challenge" out of GW... see how easy it is to rely *just* on them
Rules: your skillbar is three PvE skills, an elite, and a rez. Consumables encouraged, but only one party-effect can be active at a time (choose between ghial, celerity, and salvation - not all three at once)
Issues: certain overpowered builds still work (Focused Anger - Drunken Master - Air of Superiority - Save Yourselves) (Selfless Spirit - Glimmer of Light) (Asuran Scan - YMLAD/You're all weaklings - Discord) albiet more boringly because you don't have all the fun utility stuff added on. Then again that stuff could be really important, and being stuck on such one-dimensional characters ends up adding more challenge. (WTB prot spirit!) Not especially hero friendly.
Diablo II
Concept: we're impatient for D3, so lets shoehorn D2 playstyles where they don't fit (GW) To really feel like old times, "rush" to bosses at the end of dungeons.
Rules: 7 D2 classes, one class per team (but probably two paladins). Each class has idiosyncratic skill lists to encourage D2 playstyles. Skills are only permitted per class if they are explicitly listed. All kinds of self-heals also allowed, as are morale-boost consumeables. Examples so far:
Necromancer: may use necro hexes, but not on an already hexed target (curse limitation). May use skills that inflict poison. May use skills that exploit corpses if they don't create more than one undead (no bone minions/shambling horror/AotL)
Paladin, P/W version: may use shouts and chants, but only one at a time on self (E.G., must end Anthem of Flame on self before you can use Stand your Ground - this is the one-active-aura limitation) May use any signets, stances, and attack skills for swords and axes. One blocking skill required.
Paladin, Mo/W version: may use any maintained enchantment, but can only maintain one type of enchantment on the party at a time. May use divine signet and all smiting prayers. (RoJ = FoH, reversal of damage = holy bolt, etc.) Same warrior skills allowed as for P/W.
Amazon: all ranger skills except beast mastery, traps, and interrupts are allowed, spear mastery is also allowed. While wielding bows, conditions are limited to burning and cripple. (fire/ice) While wielding spears, only poison is allowed. May use juggernaut summoning stones (valkyrie)
Issues: not very unified. 1:1 skill corrospondence is possible to map out, but that seemed even more complicated and unnecessarily restrictive. Modifies in-game behavior, which requires more discipline than setting up skills/equipment. Some archetypes are primary/secondary combos which limits which characters can play. Need decent healing support without resorting to true healers (the game relied on potions) Not much resonance for non-diablo people (a fair number of active players now.) GW seemed to have ripped off D2 enough that it's not all that different either.
General philosophy statement: I don't think the customary ban on PvE-only skills makes sense anymore. With the pve/p split anet have thrown balance out the window and there are a number of completely overpowered "regular" skills now, and those need to be considered too when one feels motivated to ban PvE skills. There's also a bunch of EotN skills that aren't that strong which could be a fun source of variety. E.G. the reasoning behind ele variant encouraged various support and elemental pve skills, while banning the absurd damage ones like pain inverter, finish him, even technobabble.
On the other hand I'd still keep consumeables banned by default unless you're going to do the legwork to integrate them properly. This is mostly because it feels lame that some money can get you past a hard part, but at the same time if you balanced your variant around consets used constantly, it would get pretty expensive. The DP-reducers aren't necessarily so objectionable, but things like celerity, or a tank stacking +100 HP bonuses are. Against everything I just said, there is the point that consumeables could be a safety valve against getting stuck on one particular mission.
Beyond Nudists
Concept: use "cursed" items, a form of nudists that heroes can play
Rules: wear full armor, but must use 5 superior attribute runes. Casters must use a "high set" at all times (+15 energy/-1 regen wand and focus). Possibly ban all % health damage reducers (shelter, prot spirit, etc.) DP-reducers/morale boost consumeables allowed.
Issues: Not sure how to handle physical attacks or ritualist items. There are drawbacks on physical weapons but they are really minor, and it's not necessarily fair that dervish/sins get 4 pips. Could boil down to an imbagon keeping people alive (it could still be difficult in hard mode, but EVERYTHING would depend on the imba...) at the same time, not sure a blanket ban on PvE skills is good.
Monster masquerade
Concept: attempt (and fail) to infiltrate/spy on monsters; a simple way of playing monster skillbars, and get the feeling you beat enemies using their bars but with superior tactics.
Rules: your skillbar must come from one of the monster types in whatever area/mission/dungeon you are attempting. Each player must choose a different monster type, and it must be a regular monster in the zone (not boss-only). To that bar, players may add a rez (signet or within monster class), the starter heal from their monster's class (heal sig for warrior, orison from monk, etc.), and a "secret weapon" (skill from outside the monster's class - possibly pve) Additionaly you must wear a holiday helm (preferably one that looks the part.)
Issues: a real mess with the advanced EotN double-profession monsters... should be some compensation vs monster-only skills too like PvE skills in their place.... healing is also very limited in most monster groups... and I dunno if people like having such fixed bars.
Barbarians Redux
Concept: way simpler implementation of BAR that is just a tweak on Samurai; mostly ends up as yellow-way
Rules: no spells, binding rituals, or forms; only norn PvE skills (BARs not trusting of other outsiders) - must use all white gear (white weapons, no insignias or runes)
Issues: it's alot of effort/inventory to set up characters for all white, but has a fairly minor gameplay effect in GW. Most touch skills are questionable (vampiric bite), but some aren't (shove/grapple) and alot of them are bad anyway. Signet mesmers are likewise questionable, but dolyak/heal sig fit perfect. Very reliant on at least two paragons to keep people alive with synergizing shouts, which could be an issue for large human teams. Completely uninviting to casters.
Undead Legion
Concept: in many systems (like D&D), heal spells actually HARM undead... so healing is very limited here. Mostly an excuse to play a low-healing variant.
Rules: Healing skills are banned, with these exceptions: life-stealing, health gained when damage done (vamprism), regen (undead are known for their resiliance!), life transfer (infuse health, or stealing from spirits) resurrection (brings you back with x% health) Must wear a holiday headpiece that looks the part (zombie mask, maybe demon mask)
Issues: this really is quite insane... people will end up as death nova sac outlets to generate minions, and be brought back instantly with unyielding aura... again risk of becoming overly SY-dependent, although minion/spirit walls are a good solution and very in-flavor.
Completely Overpowered
Concept: focus exclusively on "overpowered" skills that "take all the challenge" out of GW... see how easy it is to rely *just* on them
Rules: your skillbar is three PvE skills, an elite, and a rez. Consumables encouraged, but only one party-effect can be active at a time (choose between ghial, celerity, and salvation - not all three at once)
Issues: certain overpowered builds still work (Focused Anger - Drunken Master - Air of Superiority - Save Yourselves) (Selfless Spirit - Glimmer of Light) (Asuran Scan - YMLAD/You're all weaklings - Discord) albiet more boringly because you don't have all the fun utility stuff added on. Then again that stuff could be really important, and being stuck on such one-dimensional characters ends up adding more challenge. (WTB prot spirit!) Not especially hero friendly.
Diablo II
Concept: we're impatient for D3, so lets shoehorn D2 playstyles where they don't fit (GW) To really feel like old times, "rush" to bosses at the end of dungeons.
Rules: 7 D2 classes, one class per team (but probably two paladins). Each class has idiosyncratic skill lists to encourage D2 playstyles. Skills are only permitted per class if they are explicitly listed. All kinds of self-heals also allowed, as are morale-boost consumeables. Examples so far:
Necromancer: may use necro hexes, but not on an already hexed target (curse limitation). May use skills that inflict poison. May use skills that exploit corpses if they don't create more than one undead (no bone minions/shambling horror/AotL)
Paladin, P/W version: may use shouts and chants, but only one at a time on self (E.G., must end Anthem of Flame on self before you can use Stand your Ground - this is the one-active-aura limitation) May use any signets, stances, and attack skills for swords and axes. One blocking skill required.
Paladin, Mo/W version: may use any maintained enchantment, but can only maintain one type of enchantment on the party at a time. May use divine signet and all smiting prayers. (RoJ = FoH, reversal of damage = holy bolt, etc.) Same warrior skills allowed as for P/W.
Amazon: all ranger skills except beast mastery, traps, and interrupts are allowed, spear mastery is also allowed. While wielding bows, conditions are limited to burning and cripple. (fire/ice) While wielding spears, only poison is allowed. May use juggernaut summoning stones (valkyrie)
Issues: not very unified. 1:1 skill corrospondence is possible to map out, but that seemed even more complicated and unnecessarily restrictive. Modifies in-game behavior, which requires more discipline than setting up skills/equipment. Some archetypes are primary/secondary combos which limits which characters can play. Need decent healing support without resorting to true healers (the game relied on potions) Not much resonance for non-diablo people (a fair number of active players now.) GW seemed to have ripped off D2 enough that it's not all that different either.