You can sort of do this already by playing the same track on 2 decks, isolating the element you want to on one deck, then cutting it out from the other.
But one that could be interesting is to be able to change the key of, say, the bass/melodic elements whilst leaving the rest of the track as is. There’s a few interesting effects from this …
- Happy hardcore style pitch up lyrics!
- Moving the pitch around on elements in minimal techno tracks is quite interesting
- I think somewhere in there you might be able to get a kind of low budget, post production 303 acid tweaking setup! Maybe when applied with gate fx so that you can cut the notes short as well as raise the pitch…
- Pitch up/down vocals so that they sound female/male