I have an idea for an AI improvement:
Can the terrain destruction ability of the AI be expanded to other missions? If yes, the AI could try to shoot some holes in the XCOM landing craft if there is nothing else to shoot at. That would create some problems for the player camping inside.
We might not be able to teach the AI how to handle doors properly, but we might be able to teach it to just obliterate them.
The idea came to me when an alien grenade accidentally blew away the doors of my ship. The mission suddenly got way more interesting.