One thing that I commonly notice in my games, is AI civilizations stacking a single square with 1 fleet (with their maximum logistics capability), and also on that square, placing about 15-25 more ships that are not in a fleet. This is a serious problem in combat, because when my fleet does combat with their fleet, and defeats it, all of their remaining ships are cannon fodder in my consequent "moves", as I pick off everyone of those ships individually. The end result is one of my mediocre fleets, defeating a single fleet of theirs, and 25 individual unfleeted ships that could have been placed in fleets, and quite easilly defeated my fleet in a subsequent attack. I've seen this in 1.0D, 1.0X.009 and the current 1.0X10. In my opinion this should be a high priority bug, as it totally undermines the AIs combat capabilities and effectiveness. Mind you this was on a Masochistic Difficult.