Yeah, it's amazing how the little details about ship xp and hit points sailed over my head completely the first 10 games or so. Coincidently, I just did a game where I was so paranoid I built fleets of massive Godzilla-like ships (5 with logistics pretty much maxed) ... in the mid-game they were superior and survived every encounter, now they have something like 185hp each, and I split them up into pairs and they STILL dominate any fleet the pitiful wretches can put together at this point.

GCII is very dynamic - meaning once you have the initiative and slight superiority, it keeps building up (or down if you're on the other side). Spies helped me conquer the Yor big-time, too. Little things like disabling their economic capitol right when I paid 3 other civs to attack them put a big dent in their apparent superiority.

Hope I didn't give away too many hints (again) !   

Ok ok have a good question (I think) ... since I usually play diplomatic/cultural at the start, the AI don't get a look at what weapons I research, or ... I start with one and switch after the first peek at their defenses. Anyone else notice that once the AI starts building say shield defense ships to counter beam weapons, they don't seem to be able to switch over to say missile defense? poor buggers were still building shield defense ships when I started putting out photon torp armed small ships .... ?