Creatures are blown all over the place when a meteor hits, with just 1 creature casting it, it's not really a problem. With 10+ doing it, things just get out of hand. Same goes for the Grenade spell. They don't bounce around like they do when in 1st person mode. They hit just like a normal projectile when a creature uses it. Combine that with a nice amount of splash damage and you wipe a full army out in seconds.
About the path finding, see savegame (latest alpha build, but the earlier ones also had the problem) creatures get stuck at about every corner with a room post. You can easily reproduce it at a temple where creatures have to walk around it. A lot of them will get stuck. When you slap them or they get hungry, they will go back to the path they wanted to go in the first place.
And another thing, Ancient Keeper doesn't work properly cause you can't dig through neutral walls. (I think it's level 6 or 7, where you have to get through a neutral wall to claim a library)