Well, I created a custom faction and managed to win one - Challenging enemies/normal critters, 12 opponents, diplomacy or conquest (I won by conquest). Final score around 18,300.

Big things I noticed were:

The spell Storm, although cool and damaging, shows the lightning blast over the incorrect unit - the one with the blast does not take damage, however another enemy unit does.

Storm Dragons, when breathing fire, occasionally face the wrong direction to breathe. 

After playing for long, long periods of time (for a few days- I'd just leave the game logged in), the game might crash and I'd two noticeable problems - the game would tell me that my save files aren't synced with Steam's cloud service and the game itself wouldn't actually run until I'd verified the game files and downloaded those that appeared to be broken.

I accepted the dragon statue quest and found one eye, but despite uncovering the entire map, no second eye was to be found (in fairness, I don't know if AI players complete quests.  One might have taken the eye, thus preventing me from obtaining it).

Having two dragons in the same party is a bit too easy, perhaps because I made a habit of killing off the strongest enemies once I had the opportunity. I might suggest limited the number of huge critters in each army in some way. If that's not feasible, perhaps some scaling in quests could be useful. I did the master quest for fun with two storm dragons and a river slag, and the boss gave me about as much of a problem as a screen full of mites. It just took awhile to kill him - there was no real danger.

Other than that, it was a blast. I would look forward to some custom race options. Creating an undead faction is on my to-do list, but prior to investigating the manual modding options, I don't know how feasible it would be.

-Void