Naga pets would be awesome.
I'd like to see:
Mini versions of the dragon Aspects (excluding Deathwing - he's already out)
The various racial leaders
Archimonde and Kil'Jaeden
The elemental lords (excluding Ragnaros - he's already out)
The Ancients (Cenarius, Aviana, Tortolla, etc.)
The Old Gods (at least the ones we've seen)
Chromatic Dragon Whelpling
Twilight Dragon Whelpling
Dreamforms (like the ones in Stormrage
Xavius (his animation could be him turning into a tree then back again)
Anetheron/Sathrovarr the Corruptor (or any dreadlord, really)
Azgalor/Brutallus (or any Pit Lord)
Supremus (I like the skin on him)
Reliquary of Souls/Devourer of Souls
Illidan (with Warglaives and glowing tattoos, preferably)
Anub'arak (or any Crypt Lord)
Blood Queen Lana'thel
I don't want much, do I?
Edit: I'm going to put additions to my list here instead of making new posts to save space.