Just had an AI player send a Kol through one of my planets to another and back again, my bombers took it down to 300 hull points before it escaped to the star. Then it turned around and came back for me to finish it off.

Also the player AI needs to start group moving, I see that the pirates do but not the AI players.

Part of the AI's problems can probably be fixed by making it "focus fire"... Just this morning, I was facing two AI empires and was barely being stressed, other than needing to keep good anti-piracy patrols. I wiped one out in a blitzkrieg (because of the stupid culture bug, I couldn't fortify behind me properly, had to rely on light pickets and the astrology to keep the AI from re-colonizing). A few minutes later, as I started to actually colonize and fortify the newly available planet, I had a HUGE fight on my hands. Pirates started attacking out the wazoo, actually causing me a lot of pain because they attacked un-fortified rear area planets (which relied on my "star-central" carrier squads and relatively weak pickets and forts to defend themselves) and central planets in large (read 30+ fleet sizes!) numbers.

Anyway, as I was busy re-allocating my fleet to try and deal with the beggening of my brand new crime wave, the AI jumped a nice, large fleet right into one of my fortified "border" planets. One that (until then) hadn't needed a garrison to fight off the usual solo scouts and small probes. (The fight was a very interesting one, they had enough flak frigates to wipe out my fighters, they used LRM frigates + bombers to take out my cannons, and had an abundance of fighters and bombers to interfere with my hanger defenses. Had I been able to properly intervene, I could have crushed it with my main fleet... but my main fleet was several jumps away, on the other side of the solar system from the planet... unless I jumped through enemy space. So I did, and ran into a jump inhibitor. The AI couldn't retreat because I couldn't "shut off" my inhibitor, I couldn't reinforce the planet because of the AI's inhibitor...).

Anyway, I ended up wiping up white with my battle-fleet because that was easier than trying to deal with the HUGE pirate fleets spawning every 30 seconds to collect my bounty. But once it was one-on-one, the AI REALLY started to take chunks out of my hide. It wasn't as good as it could have been, but I suspect part of the problem is the AI just can't pay attention to one thing at a time, and limit itself to ONLY harrasing everyone else.