I'm really just hoping for the likely return of Maude and Booberella. I had just joined last year, and wasn't into buying premium characters, though I did buy either Kang or Kodos (the one that wasn't free) and was able to get the Drive-In theather with Mutant Alien thanks to donuts won from the event. Now I've purchased and saved up enough for both of them, and Maude is the one I'm most looking forward to getting.
I'd also love it if they introduced a skin for Maude that made her appear to be alive.