I really do enjoy AI war so don't get me wrong, I'm not harping on the game because I think it's bad, much the opposite, I do it because it's really good and there is a lot of potential for it to be even better.
I do strongly agree with the original poster. The AI is quite docile and is very rigid in the way it reacts to player moves. The game doesn't have a lot of forward momentum as a result, the choice of what happens and how it happens is really entirely up to you. The game would be perfectly content if you just sat there and did nothing for hours on end, nothing would really change.
By and large there's no real struggle against the AI. The AI has no real means to overpower you and you have no real means to limit the power of the AI against you.
Aside from your direct actions against the AI, the AI only has two methods in it can attack you. It launches regular wave attacks, and every 3-5 hours or so it sends out a rather large cross planet attack. But even these aren't really interesting. Both are scheduled, the AI doesn't use them in a reactionary fashion, they aren't used as part of a plan, they just happen. The strength of the waves aren't even in the AI's court, they're based on AI progress, which is a value that you control, not the AI.
Even if the AI is an entity that spans the galaxy, it doesn't really have a galaxy wide presense. Attacking an AI world, sometimes ships on that world will react to your presense, but the AI doesn't make a concerted effort to counter your moves. In fact, unless you're fighting a Tag Teamer AI type, the AI often won't even move ships to attack your forces within a system until you threaten the command center.
The AI literally makes ships out of nowhere, which works thematically but it also means you can't get a one up on the AI. Your actions cannot harm the AI, the AI is invlunerable to harm. You can't really go out of your way to stop certain AI behavior, the AI will do what it does more or less without reguard to what you do. It is interesting that everything you do is for your own personal use, rather than attempting to hamper the AI ability to stop you into the ground, but it also makes the game a lot less personal.
After playing the game for a while, you don't feel the AI is an opponent. You're really playing the game against yourself. It's like playing a game of chess, where one player starts normally and the other has pieces aranged out on the board seemingly at random. The opponent doesn't make moves. It will take your pieces if you move them in a position that it can attack you, but otherwise, it does not make moves. The ball is always in your court, and more often or not you can use your advantage as the only active player to force the opponent to make bad moves. It's a neat thought puzzle, but it doesn't feel like a real game unless the other player is going to have to start moving their pieces on their own.
I do a lot of things to make the game feel like I'm in danger of losing to something that isn't completely my own fault. I play on cross planet waves, and I turn off wave warnings. I play on grid style games where centralized defense is rarely possible, and I play against AI archtypes that are agressive in nature. Still, the AI has a very finite scope in which it can make decisions against you, and has no thought beyond decision making for individual ships (and to be fair the AI control of individual ships is really good), but if you play the game well, winning should be a foregone conclusion. And playing a game for 10-20 hours when you already know the outcome is a difficult proposition!
I really ranted it up, I should think of some solutions to some of these problems a bit later.