I'm generally enjoying this game and think that a lot of imbalance and hopefully the memory leak issues can be resolved quickly. What really needs work though, is the AI. I know the developers are going to be focusing on this, but something must be wrong with some of the basic algorithims and strength calculations that could be fixed quickly. These examples were on Hard:

1) Suicide sovereigns. They come at you with a modest stack and attack your cities, die and that faction exits the game. When they attack, the probability of victory isn't even close to 50/50. When I approach an enemy city with a sovereign, or any unit for that matter, I look at what is stationed in the city and make a reasonable guess as to whether I can win. If not, I leave. The AI doesn't do this. They attack and die. I'm thinking that either the AI doesn't "look" into the city or the calculation of relative strength is off. Maybe the AI doesn't factor magic ability into the relative strength of a stack? Or ignores ranged abilities like archers? Not sure, but I'd think it's a simple algorithim to write that says add up all these stats for the units defending the place I'm going to attack, compare to mine and if less than 60/40, don't attack, and if my sovereign is in my stack, odds need to be 90/10 or better.

2) Declare war then do nothing - lose war and refuse treaties. The AI loves to declare war and then do nothing for hundreds of turns. Then, if you ask for a peace treaty, it's like 50/10000 and there's no way to get it done. I, as a Kingdom, had a large wealthy city right on the border with an Empire that also had a large wealthy city on the border. They declared war, but did nothing - ever. My city was defended only enough to fend off creature assaults (figured I could teleport my sovereign if needed). Eventually, I sent a stack to attack the AI city and lo and behold, only a couple of units. I captured the city and hunkered down, thinking that the AI's army would be on its way....nothing. Attacked and razed two more cities (nice ones)...nothing. This was an Empire that supposedly had 4x my "power" score and twice my population and refused to sign a peace treaty, even after taking three of their cities.

Clearly something is fundementally wrong with both the diplomacy and the AI behavior. It's not even a matter of the AI using a predicatable strategy. It has no strategy! I realize that programming a good AI is one of the hardest parts of the project, but Stardock eventually figured out a pretty good AI for GalCiv2 so I'm surprised that this one is performing so poorly out of the box. It will limit replayability if not fixed, leaving only multiplayer to get a challenege. But of course multiplayer on a 4X game requires massive schedule coordination among players and frequently falls prey to the killer-strategy problem, which saps the fun out of it (for me anyway).