I read someone complaining about weak spells in the game. I want to emphasize how much the MAGIC SYSTEM is important. This iwas imho one of the reasons why MoM was such a great title. In particular:
1) there was a nice VARIETY of spells. Some to cast in combat (and interestingly some affecting all units in combat, some on single units only) some on cities, some for war, some for movement, healing, protection, productivity, happiness, some to create permanent mutations on units, some to teleport... and most of all, I liked Global Enchantments
: at high levels a mage should be able to affect a whole reign with a spell.
2) spells were POWERFUL. You could not afford ignoring spells in MoM. Mastering the right spells was a big advantage in combat (maybe at times even too big, remember Tauron casting Flame Strike on all your units every turn at Impossible level?). I think in FE one should have the option to develop magic more than might, or conquest, or tech, and this option should be worth. If you make Magic just as "something nice to add", this would be a BIG delusion. I was highly disappointed by Age of Wonder, for instance, where the ice-storm global spell was quite weak and ineffective against enemy troops. While in MoM... causing permanent Meteor Storm on the whole world, or stopping time
- these were the things that made the game incredibly fun to play. Obviously, these spells should be hard to research and costly to cast, but there should be such spells in the game.
3) spell realms were quite DIFFERENT: only some of them could heal (and in different ways, one through regeneration, the other through direct heal) only some of them could boost units (and again in different ways: permanent mutations, armor, absorption, flight, invisibility, different immunities, extra attacks (gaze, stoning..)), only some could counter spells, or increase movement. Choosing different spell realms meant changing your playing style and strategy.
I think in a poll before the release of H:WoM the magic system ranked very high among players' priorities: please do not underestimate how important it is to have a diversified, powerful, balanced spell system - with cool graphic effects I'd add

Good work guys! Live up to our expectations!