Oh, well there is part of my problem - I didn't realize that Gnoslings had Metamagic affinity. That certainly helps them. Still, Thades should get spells more commonly, and be able to attack. Not sure about 5 strength, they are probably okay as-is.
As far as the cost of the Vault Gate, right now it is definately too expensive for what it provides you with. Considering the cost of the buildings required to actually get the units (especially the Meditation Hall; both the Meditation Hall and the Alchemy Lab are probably the ones that are overcosted. If the Meditation Hall doesn't get it's extra Sage back it's WAY overcosted) the Vault Gate needs a cost reduction. The Planar Gate is probably fine, just because it gets you a lot of very useful units.
As far as new units for the Vault Gate, here are some random ideas I've thrown together; no idea if they are balanced or anything 'cause I'm really tired right now ^^; That's also why the names suck.
:
Monolith - A massive being of living stone, infused with ancient magics. Unitclassless, with high defense, Monoliths can't move normally but can rebase instantly to any town like Hawks. They can also cast Wall of Stone and Inspiration.
Notes: Seems like something that would be hugely useful for city defense, like a magical tar demon. Should probably be linked to a moderately high level building so you don't get too many of them.
Manawisp - An etherial creature of pure, sentient magic. Has 0 strength, is unitclassless, and has no innate abilities. However, it can explore rival territory and can use its Mind Siphon ability to learn all Adept and Mage level spells known by a unit on the same tile as it - friendly or neutral.
Notes: Would be balanced just linked to the Mage Guild. Both gives you an extra caster, and the ability to steal spells from your "friends". However, with no strength, you'll have to be careful to keep it alive.
Vault Guardian - Powerful beasts that guard the entrance to Ohgma's vault. Good strength and horseman-like movement make them excellent and defending your territory. However, they lose nearly all their strength outside your cultural borders, making them poor attackers.
Notes: An alternative to the Monolith (or maybe have both if you really want to emphasize defense for the Ohgma-Kahdi). It should have a promotion that gives it -100% strength and +100% cultural strength, so that it's attack power is vastly reduced outside your culture.
Anyway, just tossing out some random ideas.
I was a little disappointed to find they are Agnostic (and I still think that's a little too crippling for them), but they are definately a very nice spin on the Amurites. The speed at which Adepts can become Followers is nearly terrifying, especially when comboed with Fireball or Maelstrom, and makes for a very nice combat mage strategy; I just wish there was more reason to build Vault Gates, as right now (especially if going Mammon path) I am sorely tempted to not bother with them at all.
