Off the top of my head:
I think "Liquids" will be added to the new unified simulation system. Personally, I don't think they can compete here with Houdini or Liquigen, but okay, the new particles system is great and liquids won't hurt.
Speaking of sims: I really hope for a big, fat "Just cache anything in this scene"-button. Mograph, Dynamic IK, just everything at once and nicely compressed to disk.
A shiny fresh viewport please!
Redshift is in dire need for an atmospheric model. I hope the groundwork they laid with a revamp of volumes allows for nice athmospherics soon...
Hopefully, there are some more performance gains possible as well. I recently opened some older, chuggy scenes and was amazed how much better they ran in the recent C4D. But speedier is always better 🙂
Last, but not least: Indie license, please!