How do you beat perfection? You can't but you sure can give people more of it!
The only real downfall is that the campaign almost has you fighting exclusively the same Black Hole COs again and again. The missions are still a marked improvement on the first's and are to be considered nothing but some of the finest gameplay experiences on any platform, but half of the fun of clearing a territory was fighting the COs of the next one. On the other hand you can choose your CO far more often and you actually play through the different now cooperating armies (for the first time in seven installments there is finally peace and some wacko terrorist group has to ruin it) and their unique COs.
If you enjoyed the original or are just looking for an awesome game, AW2 is a must, but don't be surprised if you feel you've played it before.