1. Hurry production should only be avalible for buildings. It doesn't make sense that you could hurry production of units anyway. I mean, even if you hire extra workers to make armor and weapons you still need soldiers, and training them takes time. You can't "hurry" training, then you would be sending out untrained soldiers on the battlefield.
Hurry production unbalances the game, since it allows you to build a large amount of strong units in a VERY short amount of time.
2. Tier 2 units should never build faster then 2 turns. Tier 3 units should never build faster then 3 turns. Tier 4 units should build be dropped to 3 or 4 turns. They cost ALOT anyway, so if you can afford building them, it should be possible in a reasonable amount of time (now i think buildtime is 6 turns if you have the largest town).
3. Tier four units needs some tweaking (reapers, titan). Drop damage, defense and offense. Increase hitpoints to make up for the loss of damage, offense and defense. This would make it easier to damage them, but they would still be able to take ALOT of damage. Maybe give some tier four units leadership and morale, to give them more of a support role (like the airship). You should also consider increasing upkeep for tier four units.
5. Flying units need some tweaking. I suggest increasing their cost (and maybe upkeep), so people use them for resource grabbing rather then for full scale assaults. It's very hard to counter fliers, since they move so fast. The only way to really stop them is to build your own flying units, but the problem is that some races have very weak flying units, so in those cases you will loose anyway. 6. Spell Changes. Most of them have already been posted, but I reapeat them anyway. Healing should be 11CP. Haste needs to be tweaked, increase upkeep and casting cost, more along the lines of static shield, cause it's a freaking good spell. Research cost for some skills should either be raised or lowered. It's kind of strange that spellcasting 1 takes only 8 turns to research, while peacekeeper takes atleast 16 with the same amount of research points. I find this kind of strange, since you can only choose one skill when you custmize your wizard, and why would you want to take spellcasting 1 when it's the cheapest skill to research??? An option to take additional spells at the start of the game rather then a skill would be VERY cool