
As far as the whole band experience goes, Rock Band 2 beats Guitar Hero: World Tour by a nose. But there are some areas where Rock Band 2 can take a lesson from Guitar Hero and be even better.
Drum overdrive. The one thing that Guitar Hero: World Tour really nailed on drums was the ability to use your energy any time you want. The drum fills in Rock Band 2 can be really annoying when you don't want to use your energy right away and sometimes revert back into the song very awkwardly, which can make it more difficult to keep up a streak. Simply allowing the drums to go into overdrive when the red and green drums are hit simultaneously (discounting those times when you are supposed to hit those two together) would help the experience immensely.
Drum fills. Now that we've gotten rid of the constant fills required to go into overdrive, we need to insert them just for fun. Freestyle drum fills really do add something to playing drums, and not needing them for overdrive frees up the developers to make an intelligent decision on where to have them in a song.
Fluid guitar. The rhythm portion of songs is done very good in Rock Band 2, but the implementation of the lead guitar could use some work. Guitar Hero: World Tour's use of sustained and smart use of hammer-on notes makes playing it much more fluid. While Rock Band 2 uses both of these methods, they don't implement them as intelligently as Guitar Hero: World Tour.
Round buttons. I know Rock Band doesn't wan to look exactly like Guitar Hero, but those little rectangles are crap compared to the big round buttons in Guitar Hero. It really makes playing the songs easier when you can easily see what is coming up -- especially when playing guitar and hitting an area with a lot of hammer-ons.
Encores! The entire cinematic experience of Guitar Hero: World Tour is superior to Rock Band 2, but in terms of game play, it's the encore that Rock Band is really missing. This would put a nice touch on Rock Band's world tour -- which is already pretty fantastic.
Suggested Reading: