Okay, I've played three games with guardian. Each one with the same setup: advanced, fair everything except minerals and power, which were both maxed.
My build was some variation of the following: 4 nature, 4 something else, myrran, omniscient, guardian, and dark elves.
I forfeited each game.
Let me first get this out of the way: I'm a weak to average player. I'm simply not on Seravy's level, or the level of most players who post here.
But I'm not a terrible player, and win most of my normal games. Also, it might be useful to have the opinion of someone not playing regularly on higher difficultly. A noob perspective if you will.
What I'm saying is I suck. But I don't think this fact invalidates my test.
I'll restrain my comments to the guardian pick.
It's not worth two points.
In each game, it seemed promising at first. I'd get raided, and my cities would be able to survive with far less damage than expected given what I had garrisoned there (swordsmen and spearman with a wall).
Then the inevitable wars started.
I thought that I could focus more on creating offensive units at my military cities, and leave other cities with weaker garrisons such as swordsmen, apprentices, the occasional priest or halberdier, with a wall. The idea being that I could focus most of my resources in creating stacks that would then seek and destroy, leaving a defensive stack behind on my home continent and each city moderatly defended.
Well...no.
From my last game: three troll swordsmen, two with heroism, destroyed my garrison of eight adamantium swordsmen + wall, with no losses. A stack of 3 dark elf swordsmen, two giant spiders, and four sprites destroyed my garrison of 8 orch-boosted apprentices + wall. A stack of 9 naga, half with resist elements, took out my city with 8 adamatium cavalry + wall. That I kinda expected, given poison, but still. I thought I might have at least one survivor.
So rather than being able to produce stacks of halberdiers and sending them at the enemy, or get to the higher-tier DE units, I had to refocus on local defense instead. Meanwhile the AI were churning out sprites, naga, war bears, and DE and troll swordsmen with life buffs, and sending them my way. By the time I was putting out gargoyles, Horus was garrisoning his cities with water elementals.
Now part of this result is due to my lack of skill. Part of it is due to what I now think is the way too high difficulty of advanced, and part of it is due to guardian not doing what it promises on the tin.
It needs a buff, or it needs a reduction in cost. I would have been better served picking warlord instead, in the hope of keeping my cavalry, halberdiers, and galleys alive a little bit longer.