[Endoperez]

I do think they are the most powerful. They have lots of units, lots of money, can go either for awesome amounts of money (order 3) or luck (order 0/turmoil 1 + luck3), benefit from resources so can get a fast start (and more money), their mages can be useful on the battlefield (magma bolts), forge some items (earth items, burning pearl, charcoal shield, faithful). But I think that is more because of the weakness of other nations. Take away the archer and give it to some nation that is weaker.

Few things that would spice things up:
*Give the animal/charmer nation Wolfherds, make Summon Animals their national spell and make it slightly cheaper. Take away most recruitable animals so that they won't have to pay too much upkeep for the summoned critters.
*For more Ielyft creatures, check the R'lyeh mod 'False Dawn '
*consider giving some nations unique starting units, kind of heroes that exist from the beginning.