As lame as it sounds, I always wanted the bounty hunters from Critters, and a few Krites. I would also love it if they could produce Star Trek: The Next Generation figures that fit in the 7" scale, but that'll never happen.
Lara Croft from the new game would be awesome, since the only figure on the market is in that lame "Play Arts" scale.
Not a new license, but I'd love to have Kyle Reese in future gear from the first Terminator movie. I'd also buy about a million Endoskeletons, especially if they revised them a bit. Future John Connor from the beginning of T2 would be awesome too.
Really, I'm fine with NECA producing any sci-fi licenses that I can display with my current NECA lineup.