My first impression is to be impressed with how stable the game is.  I don’t think I’ve had a single BSOD or CTD while except for when I’ve reloaded games or used the <CTRL><N> to restart a game. 

1. In one game, my capital city disappeared twice.  But this is a known issue and I expect the next Beta release will fix it.
2. There have been a few occasions where I could not get one of my armies to move.  I’m pretty sure it was not because they had moved their max turn allotment. I’ll try to capture saved games on this if I catch it in time.
3. <CTRL><N> or Reloading a saved game causes CTD.

I’ve also ran across a few major annoyances.

1. Rotating the map orientation is very slow using the <ctrl> <arrowkey> combination.  I have yet to figure out another way to do this.
2. In tactical combat, the tool-tip windows are too close to the cursor and obscure the units I’m trying to target.  This is most annoying.  For some reason this seems to move around though and I’m not sure why. (edit: Problem is caused by rotating the tactical map)
3. On the actual town, there is no way to identify what building is what on the map.  As in there is no tool-tip or way to select an individual building.  The only way to find out what each building is it to select “Demolish” and click on the building.  Fortunately, there is an “are you sure” dialog do you don’t have to demolish the building to find out what it is.
4. The cursor icons are not changing shape as they should.  This is minor stuff but it is there.

Now on to my game-play thoughts:  Overall, I think the game is a vast improvement over E:WOM.  But I will list below some of my thoughts and opinions.

1. I admit that archery was overpowered in E:WOM, and the -100 strength bonus/penalty, addresses that issue.  But I think -100% is too much.  It makes putting bows on champions almost a waste as the damage does not scale up as they level.  In my opinion, the lowest level bows should be -100% but that each more advanced bow should reduce the penalty by 10% up to a max penalty of -50%.  That way, it allows champions to be archers without getting ridiculous.  A champion with archery maxed should be able to do 75% of the damage  that a champion Fire Archmage with one or two Fire Shards casting a Flame Dart.  The Fire Archmage will still be more versatile and useful.
2. The Fire school is easily the best school for tactical combat.  But Air with Haste and Titan’s Breath is pretty good too.   I would like to see Air get a AoE lightning spell similar to Fireball.
3. I think Earth and Water can use some love to improve their tactical uses.  IIRC, Earth has Slow.  I can’t name a single worthwhile spell in Water for tactical combat other than summoned elementals.  Perhaps Water can get some nice buffs or something like that.
4. Speaking of buffs, except for haste and slow, tactical combat seems to be missing buffs and debuffs (unless you count Titan’s Breath). 
5. I can’t discover any way to make bare terrain habitable.  A “Gaia’s Love” Earth spell to turn a section of barren terrain to fertile would be a welcome addition.
6. As it stands now, no sovereign or champion can learn a school of magic they didn’t have at creation.  In some ways, I like that so long as you get a reasonably good variety of champions to recruit from.  So for that reason, I would like to see some way to research or earn different schools of magic.  I understand that random chance on start is part of the way these types of games work, but with Starting Position, you can look around you fairly early and get a feel for how good or bad your start position is.  But you have to get fairly far into the game to determine how you’ll do on champions.  Few or poor champions can be a big hole to climb out of and it sucks to realize you’re screwed in that regard many hours into the game.
7. Dodge is VERY powerful.  I have a tank with tons of dodge on him.  He’s a fantastic tank because he’s  bitch to hit!  
8. Haste is also quite effective especially when used in conjunction with Titan’s Breath.
9. The healing arts of Life school are also very effective.  My Dodge Tank (mentioned above) and my Life Mage make a very effective combo.  Toss in a good Fire or Air mage for offensive spells, and you have a great army.  I got my tank, healer and sovereign Fire/Earth Mage teamed up fairly early and they generally managed to defeat all comers.
10. There needs to be a percentage chance that a defeated champion will actually die.  On the one hand, it sucks to lose a champion, especially for random bad luck.  But, on the other hand, you get tired of defeating opponents’ champions over and over again.  Perhaps perma-death should only occur if the party is completely wiped out or perhaps have a limited number of times a champion can resurrect back at the nearest city. 
11. I wish I could understand the relationships between stats and what happens in combat and is spell casting.  Right now I’m wondering exactly what Intelligence has to do with Magic.  Same with Dex and Str on melee and ranged combat.
12. I’d prefer party size to be set at 8 at the beginning of the game and remain there.