Well, just finished my first game on Hard, medium random map: Here's the horrible bugs I found:
The computer did'nt retreat all the time, it stayed and fought, especially if there was a Starbase! Forcing me to build an actual well thought out fleet to attack it with.
Carriers/Strike Craft seemed balanced; at first they swarm you as usual, but if you can hold them off and cut them down, they stay down, and Flak ACTUALLY helped! I was unable to get my "Mass Carriers parked on the edge of my enemies well beer", and had to stay and do a bit of micro.
The Vasari Starbase did not collapse like an elderly person with a walker; it fought hard and took out several of my ships. I was actually forced to retreat, and come back with a more apropriate fleet that also included Missle ships What a pain.
The new "Qucik Start" setting forced me to miss my "begginging of a Sins game nap" and I had to play wide awake And since the AI kept moving in Starbases to my totally undefended planets, I missed my mid-game nap too.
The AI now also has a bug where it STEALS your resourse asteroids in uncolonizable wells; this forces you to keep having to sit up and watch the screen and stuff so you can defend those wells occationally.
I hope they can fix these bugs before the 25th. . .