I've had it since it was released, but my first impressions were that the ZC were totally overpowered (laughably so, and confirmed numerous times when trying to play against them online), the campaign was too quick, there was a conspicuous lack of campaigns for the rebels or empire (there should have been campaigns based around the 2nd death star ala ROTJ for both factions), and there was STILL no Lando Calrissian or Leia...it's just not Star Wars without Lando and Leia!
And being a bit of a purist I thought FOC was based way too much on expanded universe stuff. That's to be expected though. It's just that to me it was too much...I especially disliked the nightsisters who used lightsaber whips and rode rancors around. Wtf is that all about?
Let me put it this way: When I got FOC I completed the campaign and a few GC games with a fleet of just starvipers (with 3 skiprays thrown in just to allow bombing runs), and land forces of mostly canderous tanks and MALs (in the campaign I couldn't use the tanks so I used pulse cannons instead). So what that the land forces cost a ton? The ZC make 10x more money than the rebels and empire combined!
I was also bothered by the scale of the death star II vs planets and ships. It looks tiny compared to ships and gigantic compared to planets. I know how it's impossible to make everything to scale, but still.