Definitely no more speed. Nagas are already amazing, insane scouts with their 3 water walking movement.
Well, Nagas are 61% as durable as Bears, and Bears deal 57% of the damage of Nagas. So on that the two units are roughly even, Nagas have a slight edge in it (or a big edge, resistance comes in much wider variety than shields, and the 6 I used in the calculation might be overestimating the real average resistance of early units). But that's the problem : Nagas have water walking, first strike, and the respective realms demand bears to be stronger than Nagas anyway, not equal. So it'd be perfectly balanced if Nagas had neither water walking, nor first strike, and both were in Nature only.
Anyway, let's see the options :
-Less movement.
This would put them back to where they were before the Sorcery buffing. The unit would be significantly weaker despite the identical stats. Funny thing is, pure sorcery can get around this by putting Guardian Wind (against bowmen type units) or Focus Magic (against anything else) on the Nagas, so I'm not entirely sure why we wanted them to be faster in the first place. Unfortunately the AI doesn't use these tactics so this would hit Sorcery AI much harder than Sorcery humans so maybe that's why.
-Less attack.
Dropping melee from 5 to 4 would reduce damage by the exact same amount the poison buff raised it so we probably should do at least this much, but probably the problem is greater than this. However dropping it even further could turn it into an entirely "resist or die" based unit that fails against high resistance enemies which would make it more unique in common summons, but not necessarily in a good way. As Sorcery has nothing else, and it might need to fight a high resistance race early, I think this option is pretty bad.
-Less shields and/or hearts.
This makes the unit vulnerable to ranged, which is good - they are supposed to be vulnerable to it and the higher movement negated a lot of that weakness. However the player can still put Focus Magic or Guardian Wind on them to negate this weakness, and Catapults can counter the Guardian Wind so this change would promote smarter play and give the edge to the human players.
At the same time unfortunately it also makes them weaker in melee - you can't always expect to kill every enemy in range with first strike damage especially if there are multiples of them. However, as making them weaker is the goal, this might be the way to go as long as we don't overdo it. (We don't want Nagas to be another hell hound)
-Higher cost
So what if a Naga is equal to a bear in combat? The important point is not to be as cost-effective, so if they cost more, it's fine. For the current Naga, let's see. +20% cost because Nature summons are better than sorcery by definition. +10% for first strike, another for water walking. So 70*1.4 = 98 mana. That's actually pretty close to its original cost of 100. In fact, as Sorcery has very few summons and will need to rely on these longer, being able to have more total force in a stack, might be desired. Another upside is a few turns of delay in the early scouting done by the unit.
-Less poison
We buffed the entire poison mechanic specifically for this unit and Ghouls to be able to fill their role as "counter early buff rush", so reducing it would be very questionable.
-Lose first strike and water walking
This would be a stupid thing to do. I have nothing else to say about it.
Overall, I think the reduced defense, health, or increased cost are the viable options.
But if I have to pick one, I prefer raising the cost. The question is, how much. 90? 95? 98? 100? 110? 115? Saying first strike is worth 10% or the realm difference 20% are just examples so we should give it a bit more though than that.
PS : we'll deal with ghouls later, for those probably the best solution is to make skeletons more desirable and raise ghoul cost at the same time. There isn't much to be nerfed on "poison 1" or a strength 3 ranged attack.
Well, Nagas are 61% as durable as Bears, and Bears deal 57% of the damage of Nagas. So on that the two units are roughly even, Nagas have a slight edge in it (or a big edge, resistance comes in much wider variety than shields, and the 6 I used in the calculation might be overestimating the real average resistance of early units). But that's the problem : Nagas have water walking, first strike, and the respective realms demand bears to be stronger than Nagas anyway, not equal. So it'd be perfectly balanced if Nagas had neither water walking, nor first strike, and both were in Nature only.
Anyway, let's see the options :
-Less movement.
This would put them back to where they were before the Sorcery buffing. The unit would be significantly weaker despite the identical stats. Funny thing is, pure sorcery can get around this by putting Guardian Wind (against bowmen type units) or Focus Magic (against anything else) on the Nagas, so I'm not entirely sure why we wanted them to be faster in the first place. Unfortunately the AI doesn't use these tactics so this would hit Sorcery AI much harder than Sorcery humans so maybe that's why.
-Less attack.
Dropping melee from 5 to 4 would reduce damage by the exact same amount the poison buff raised it so we probably should do at least this much, but probably the problem is greater than this. However dropping it even further could turn it into an entirely "resist or die" based unit that fails against high resistance enemies which would make it more unique in common summons, but not necessarily in a good way. As Sorcery has nothing else, and it might need to fight a high resistance race early, I think this option is pretty bad.
-Less shields and/or hearts.
This makes the unit vulnerable to ranged, which is good - they are supposed to be vulnerable to it and the higher movement negated a lot of that weakness. However the player can still put Focus Magic or Guardian Wind on them to negate this weakness, and Catapults can counter the Guardian Wind so this change would promote smarter play and give the edge to the human players.
At the same time unfortunately it also makes them weaker in melee - you can't always expect to kill every enemy in range with first strike damage especially if there are multiples of them. However, as making them weaker is the goal, this might be the way to go as long as we don't overdo it. (We don't want Nagas to be another hell hound)
-Higher cost
So what if a Naga is equal to a bear in combat? The important point is not to be as cost-effective, so if they cost more, it's fine. For the current Naga, let's see. +20% cost because Nature summons are better than sorcery by definition. +10% for first strike, another for water walking. So 70*1.4 = 98 mana. That's actually pretty close to its original cost of 100. In fact, as Sorcery has very few summons and will need to rely on these longer, being able to have more total force in a stack, might be desired. Another upside is a few turns of delay in the early scouting done by the unit.
-Less poison
We buffed the entire poison mechanic specifically for this unit and Ghouls to be able to fill their role as "counter early buff rush", so reducing it would be very questionable.
-Lose first strike and water walking
This would be a stupid thing to do. I have nothing else to say about it.
Overall, I think the reduced defense, health, or increased cost are the viable options.
But if I have to pick one, I prefer raising the cost. The question is, how much. 90? 95? 98? 100? 110? 115? Saying first strike is worth 10% or the realm difference 20% are just examples so we should give it a bit more though than that.
PS : we'll deal with ghouls later, for those probably the best solution is to make skeletons more desirable and raise ghoul cost at the same time. There isn't much to be nerfed on "poison 1" or a strength 3 ranged attack.