well, i think an interesting question would be
does playing liszt improve your bach playing, more than playing bach improves your liszt playing?
to those people who recommend bach to improve everything, this is a bit shortsighted, the pianistic techniques bach worked with are very primitive compared to liszt.
playing bach conciously improves articulation, clarity, and control of multiple voices shared among the hands and fingers, but it doesnt improve your octaves, biatch!