One other thought for Dresden or whoever is looking at battle AI (if anyone) - I love playing with the ultra unit sizes, and I really don't play naval battles at all. But one thing that does cause me some suffering is any naval invasion / combined assault against one of my cities. I usually want to play these battles & I have found that when enemy units disembark it is a mess trying to fight them. You can't rightclick-attack them, sometimes missile units cant target them etc. But worst of all, often the enemy units will just stand around doing nothing immediately after disembarking & cannot be targeted at all. Usually in this case, the player ends up having to wait out the battle because you can't kill enough of them to rout them, as some of the enemy units aren't actually there.
SO - that is a longwinded explanation of the problem. My proposed solution is to implement a priority for disembarking AI troops to storm directly to the city center first, rather than trying necessarily to kill my troops first. It certainly isn't ideal, but at least they might try to actually fight in that case.