My problem with this is that it's not gonna be fun. Reserve feats are, at best, very "meh" in their usefulness. They scale alright, but they are like highly unoptimized blasting, the wizard equivalent of a sword-n-board fighter. Some of them are kind of interesting (The borne aloft one comes to mind), but they're very, very, low-level abilities.
Here's the thing: the vast majority of DnD is combat. If all their spellcasting is a minute long, they will never be useful in combat. It's a bit harsh, but combat is far too fast for even a 3-round spell to be of much use most of the time. Spending that long in one place, without much else to do, and you're not contributing to the party, unless you've got an auto-win coming out your sleeve.
Now, if this class is *supposed* to be all useful outside of combat, then there are still some small changes I'd make. It's great for that, but you can probably give it at-will for most of the spells (with maybe a few like Baleful Polymorph kept on a separate list), with a restriction of, say, a few minutes between casting. That last bit may even be unnecessary, what with the list they have. Most of that won't be useful if it's cast multiple times, and if it is useful (say, detect thoughts...? Dunno. Couldn't find any on the list that would be cast really abusively out of combat), it won't break the game.
All in all, my recommendations! Remember first that I think this class has a ton of potential, and I like the mechanics you've set up. They just need more flesh and options.
1. Give the out of combat options a boost.
2. Give the class some decent in-combat options (maybe related to buffing others, or detecting what the enemies' strengths are?)
3. Make new reserve feats. That spell list has a lot of areas where you could do more, and if you made new reserve feats, there'd be more options.
4. Lower casting times at least a little. If it took me an hour to cast a fireball, I'm 90% sure my party would buy a scroll and tell me to read it. OR the entire game would be, "hide and wait so the caster can sorta be useful in the surprise round." I think full-round casting for most spells, two round casting at MAX should be sufficient to really force the player to think strategically.
4.1. Alternately, make lists of which spells take longer, relegating more game-breaking spells to longer charge times.