Scootaloo, Sweetiebelle & Spike, please!
I'd like to have more pegasus molds in general, but I have wing-bias.
If they're gonna re-release the mane 6 all over the place, how about a new mold or three? Hasbro has shown they're more than willing to produce molds that are pretty much one-offs (Granny Smith rules!) & we already have PTS, so maybe a walking, hat bearing AJ or a bouncing Pinkie? Give Luna her own mold now that the other 3 princesses have their own. I'd also like to see more random ponies & non-pony critters.
Don't really have any play set ideas, not really into that. A nice, figural display unit, perhaps?