Here's a list of stuff I'd like to see:
Definitely AI surrender. It's annoying to chase down a players last few asteroids when it's beyond hope. Offer it as an option, because if the computer was especially difficult I may want to take the time and enjoy utter annihilation.
Diplomacy: I don't understand the way it's set up now. Why should I divert a major portion of my fleet to go deep into enemy territory (sometimes going past two other players) just to get a diplomatic bonus that disappears so easily? It needs to be more flexible and reworked. Maybe aggressive diplomacy (like kill 10 ships of player X) should occur after a strong relation has formed through more passive means beyond giving player Y so many credits or ore. Maybe even dynamic options, like a neighboring AI calling for aid. If you assist him in battle, I'm sure it would go a long way to demonstrating your good intentions. As of right now, the only way I complete diplomatic missions is by accident. There's no incentive for me as a player to plunge a significant portion of my resources into missions that offer unsubstantial and fleeting rewards.
Defense: I completely agree that defense should only serve as a deterrent. Who wants to play a game where someone can dig a bunker and bulk up until one massive apocalyptic force rips through system after system? But, right now, certain elements don't work. Here's an example: turrets are a waste of tactical slots. You have two options: concentrate their position, which can actually become an effective deterrent, but becomes useless as a player can fly right past them, or spread around the planet minimizing weak spots but also eliminating their ability to do anything but spit peas at a Goliath. Their range needs to be extended, maybe even a slight buff to damage. Something, because, it's not working. (I also think regeneration docks' range needs to be extended). As of now, I found the most effective defense is to strictly use hanger bays. So, if that's true, why even have anything else?
More map options! I respect and acknowledge the dudes at Stardock lovingly and agonizingly crafted the original maps to give me the best player experience, but please, let me screw it up if I want.
Siege frigates: You're really close. But, I still think they're primarily used as guerrilla raiders rather than sieging weapons. Think medieval. Could I roll in eight unattended trebuchets against an averagely defended castle, wipe it out, and roll back out? Don't get me wrong, keep them powerful, but maybe a little bulkier, slower, weaker in the shield department. Basically, I'm trying to say these things shouldn't fly solo.
Pirates: If the opposing player has a bounty on their head, and I'm attacking one of their outposts, please don't drop a pile of Yargh's in the middle of the battle and have them attack my guys.
I know that's a list, but take it and the time and thought I put into it as evidence for how much I enjoy this game. Seriously, I haven't been this obsessed in foreverago.
I love it!!!!!!!!!!!!!!!!! (<-see how many exclamations???)