Yup, the AI is bad.
And as many know, the excuse "this game is made for multiplayer" doesn't realy work today.
Sometimes I think I myself, alone could make a better AI on the Warcraft 3 engine (which is based on C programming language if that matters) than what we have in demigod.
Instead of making the AI "cheat" in gold and experience (that's totaly bullshit) I would make the AI cheat in something else 
Like what is the AI good at (and PC's in general)? Counting numbers!
So why can't the guys at Stardock make the AI cheat by making some extra calculation, like a situation:
An AI is chasing some Demigod with low hp's. Maybe 2-3 hits and it's dead. So how could the AI "cheat"?
It could calculate it's own speed compared to the other demigod, see how much hit points it has, what damage and rate of fire do towers have and how fast will the towers kill the AI? How much time will the AI need to kill the low HP Demigod? Will it be a good idea to try to kill the demigod based on the calculations? Will the AI be able to escape without dieing?
After making these calculations that will be completely invisible for the normal players, the AI concludes:
Hmmm.... I will kill the guy in 6.3 seconds, but the towers will deal too much damage to me and when I attempt to get out of there, I will die 99%. Hmmmm.... *Randoms a number between 1 and 100, which appears to be 27* Well, I guess I better leave that guy and try something else *AI retreats*.
And about UB or any other demigod, I think that the game is pretty balanced, but the AI just appears to be playing some Demigods better than others (like it totaly kicks ass with Regulus and Oak, but sux for Rook).
