We've seen GHIV's drumset, as well as the ION kit for Rock Band. At this point, for Rock Band at least, cymbals would only serve as gimmicks, since you could hit the same colored drum and still score.
My idea is to implement those "hammer on" notes into the drum charts. For example, a "hammer on" yellow would indicate that you need to hit the yellow cymbal for a hihat note and a regular size yellow would indicate that you need to hit the yellow pad for a tom note.
I know Harmonix isn't going to keep the same drum design or gameplay options due to competition from the currently unreleased, but generally regarded as superior drum component of Guitar Hero IV.
A major concern for current Rock Banders is backwards compatibility for DLC. If this idea is implemented the charts won't have to be changed, as the notes would still stay the same saving work that would be wasted mapping another color. The only change would be the size of the notes, and figuring out which note is what shouldn't be that hard. This would be a mandatory download, hypothetically, for those who want to play their old DLC should a new and improved drum component release with RB2.
This would add to the realism without drastically altering the charts as you still only have four colors and the bass pedal, saving much needed chart space in a full band environment. Guitar Hero added another color and 2 cymbals. Should this idea be implemented, we would essentially have all the major components of a basic drum set: snare, hihat, ride cymbal, crash cymbal, 2 rack toms, a floor tom and a bass drum.
This would mean adding 3 cymbals to the current drumset. Although I think the quality is extremely low, I think the current drumset is relatively well designed. Harmonix could release a plug and play (which has already been done actually) cymbal pack allowing for current Rock Band drumsets to function with the hypothetical sequel alongside a standalone drumset including cymbals, giving much more incentive to purchase the new game for current consumers. Assuming it all holds together, this would trump GHIV anyday!









