I'm an advanced DDR player and for the songs with a rating of 6-9 feet require you to tap the panels in quick succession.
The main design flaw with all consumer dance platforms seems to be the rate at which the panel can register taps. Sure, they work fine for easy tracks, but when you try the harder tracks you find they cannot register your moves at all.
By my estimate, you need be able to register 6 taps per second ON THE SAME panel. This said, how does your solution perform in comparisson?
Btw, the DDR platforms in the arcade use membranes to register the panel hits.