i'll chime in as well with my predictions for r20:
- prorender improvements, but probably it will still suck a** compared to other gpu renderers.
- viewport improvements, while i hope it will be significant, i somehow lost my faith that we will ever get a viewport performance anybody would call fast.
- some minor character animation tools improvements.
- nodal material system (they just can't not do this any longer)
- some rather small mograph additions/improvements
- some bodypaint improvements.
- probably some vr stuff
what i don't think we will see in r20:
-any kind of particle stuff, they know pretty much everyone settled for xp.
-expresso updates (i don't know why, just a feeling)
what i really wish for is significant viewport performance improvement and character tool enhancements. pretty sure we will see both, the only question is to what extend. and of course also the nodal material system, although i'm rendering in redshift most of the time anyways these days. also some additional hair tools would be nice.