Well...
I remember that my old Roland G800 had the option to mute some of the percussive instruments ( I seem to remember that there were three buttons to mute different classes of drums, like bass-drum and snare, cymbals, latin percussions...); this would solve the problem of "busy" drum tracks, but when it comes to other instruments things are more complicated.
For example, I find that the Tyros 2 has styles a bit too busy and sometimes even obtrusive; it's like Yamaha programmers were willing to show off what the Mega-Voices could do, but the result is that in many cases I have to lower the volume of a track or two or mute them at all, because they clash with what I am doing with my left hand. Sometimes just choosing a different instrument solves the problem, maybe because it's only a matter of frequencies, so -for example- if I replace an acoustic guitar with a jazz guitar the new instruments takes up a different place in the frequency spectrum and the problem is solved.
Luckyly, as Rikki wrote, the Tyros 2 has multipads as well, and with lots of options to choose, and this sometimes offers a solution to the problem, because I think that as of today asking the manufacturers to program multiple patterns of the same instrument for each variation would be a bit too much, and would no doubt add to the final cost of the instrument.

By the way, speaking of multipads, can anyone comment on the quality of the PA-800 multipads compared with Yamaha?