Well, I'm into glitch/granular/quasi-chiptune sort of stuff, but also like more classical stuff - strings and winds, - and I had no problem finding necessary sounds in Maschine. Of all DAWs I know, I think it has literally the best library and only Ableton Suite can compete with it, in terms not of quantity of presets/banks/instruments but rather in their quality and distinctiveness. But if you're asking, I'd probably go with some wobbly stuff - basses/leads with non generic customizable parameters that really affect the sound to alter/tweak it realtime. Not plain cutoff and reso, but something more weird. I'm into knobs at all, so my desire is to have an ultimate, beyond the usual control on instrument. If some of the new ones would offer that, I would not especially care how they sound at all, and would be really grateful. Talking about music I produce, it's, well, noise/idm, avant-garde, indietronica, a bit jazz and electro/proto-dubstep here and there...
Hope I was helpful. One more thing: if you in NI have your own priorities of what you want to concentrate on for a new extension pack, you can give us an idea, and I won't hesitate to write what of this seems the most important to me. Also I like kits like circuit bent and workshop, and if you could add more kits that sound off the beaten track, that would be just great.