Thanks for adding my request.
However I dont think more styles for rock is enough.
I think a major distinction for rock is that drums and bass are usually very different between one song to another, just the progression does not give enough feel of the song. I cannot imagine just adding more styles as being enough to make many rock songs to sound significantly better. I think for rock something else is needed... therefore I propose for instance the ability to combine gp (or midi) sounds.