My hopes: multi-timbral (at least 8 parts).


Vintage DAC modelling, for all the classic artifacts.
It's more than just DAC though, it also has to do with how the FM chips handled math.

Based on this video, a lot of those old Yamaha FM chips had some interesting artifacts:


Another big hope is the ability to modulate individual operator pitches, with a sequencer like the Wavestate. You'd be able to do some crazy stuff that way.