Re: what new minis I'd like to see, here's a few I wouldn't mind being able to plunk on the table (keeping in mind that I'm playing 3.5e and don't know if they've all been carried over to 4e, and I really use them only in my campaign):
-- A few more iconic fey creatures, but especially a pixie. I've always been surprised this has never made it into a set.
-- Skulks.
-- Like an earlier poster, I'd like to see a few more minis that aren't obviously waving a weapon around. A couple aristocrats would be nice, maybe a merchant; they could have weapons in belts or whatnot but not be waving them around. Or they could be described as spies, enchanters, illusionists or what have you that wouldn't necessarily rely on blades to do their damage. And I could use them as NPC's in all sorts of encounters, some combat oriented, some not. And how about maybe a bouncer?
-- More common skeletons, kobolds, zombies, and orcs. I was thrilled to see the skeleton, kobold, and orc in this set. More!
-- A common shocker lizard. Another one I'm surprised has never made an appearance.
-- More animals and vermin: baboons, common small spiders, a bat swarm, fire beetles, centipede swarm, stuff like that. Maybe an elephant rider? More familiars could be nice too. I know that a lot of animals can be found at stores like Michaels, and I wouldn't want WOTC to make stuff that just duplicates those, but there are some creatures that you can't really get at the right sizes, or indeed at all.
-- An assassin vine. Another one I'm surprised hasn't been done.
-- Demodands. Never a single demodand so far.
-- More common thug types -- not soldiers, not mercenaries, but thugs. Can't have enough of those.
-- Someone earlier mentioned tribesmen, be they Aztec or whatever. I want to second that.
-- Some kind of common ooze or slime that I could get a ton of for when they multiply.
-- Love the volcanic dragon in this set, now I want one that's Huge! Don't really expect it, though :-(
-- For the next Colossal or whatnot, how about the Tarrasque?
Here's hoping! Thanks for asking! And for the record, I really like what I've seen of the next set; even where I don't think I'll use them, the level of artistry that went into these seems better than usual, and sometimes really magnificent. (That hydra, OMG! I hope someone got a good bonus for that one!)