DDR worked because the marketing angle of it as a "casual" game with exercise benefits was perfectly functional. DDR is pretty easy in general, even if they're tacking on retarded boss songs on the upper tiers these days.
Unfortunately, KDE seems to think that this is the only way to sell their games. This is dumb, because everything else in the Bemani series (short of the silly things like Dance 86.4) is HARD; watering it down doesn't really work because the basic gameplay itself is a key part of the difficulty.
I think jubeat can reach moderate success as a cooler Whack-A-Mole, but there's no home version (and such a thing would probably just not happen because it'd be stupidly costly), and it doesn't have that exergaming bent, so it's not going to hit DDR levels.