Some of what TheDog posted is how i feel as well but not all. My observations will differ a bit.
All around i think the game is well balanced. Since there are four races on each side the randomness of the resource placement and helpful items means that IF you are playing only one of those races, the other three are almost guaranteed to have more of something you lack. You just need to figure out what you need to specialize in to be an effective ally.
As to units, i think the current stats are mostly fine. I agree with TheDog that cavalry could be a bit more costly in food. I don't agree with his take on bowmen and crossbowmen. These to me seem to have been intended as basically improved Irregulars. Either gaining a defensive or offensive bonus but still basically Irregulars. The cost for them is not much more in PU's but you have to pay for the bonuses in food. I don't have a problem with that. Especially in the later game when there is such a huge surplus most of the time.
I don't agree with the take on artillery either. Its a nice way to have powerful attacks like a hero when your hero is not present. Or if you do not have enough mana or gold for whatever reason to buy the good supporting units.
I do agree that spells are a bit O.P. with their range, 4 seems excessive. I also agree with the troll Berserkers not being worth it. I have not once bought them. The Fire Canoe i also agree with. Its basically pointless. At that speed its almost purely a defensive weapon.
All in all though like i said this game seems very well thought out. If the technical glitches can be ironed out it may well be a favorite of mine.