Well, me, I'm a big fan of Wish: It's so awesome, and there's so much stuff you can do with it. I mean, even the name is awesome.
The alteration school contains a number of very nice spells, such as the battle buffs like Mirror Image, Mistform, Body Ethereal, Personal Luck....all of those are Alterations.
Fire flies is indeed the result of neglecting to study evocation. While there's a ton of spells which perform similar tasks and do better in similar roles (Blade Wind, Nether Darts), you certainly get what you pay for with Fire Flies.
Hordes from Hell is not as lame as you make it out to be, though: The cost is relatively modest, and it's a remote-summons. You can cast it at any target province, and the aforementioned hordes from hell will appear. While not powerful, you can shotgun them all over the map and drive your opponent absolutely nuts. It's not something you use against hardened targets, but it's not bad at raiding and generally raising hell.