pitch shifter module
I'm really keen on the idea of a pitch shifter/corrector module. Something would allow for some realtime pitch shifting (anyone remember the Sound Blaster realtime pitch shifter that people used to make that stupid "wheeee" squirl voice?) as well as correct vocals and such.
This module could have several pitch shifting methods, similar to how Live has a variety of shifters. One of those shifting methods could be granular synthesis for sure. Maybe another could be a nice formant shaping shifter like Melodyne has.