Biggs Darklighter in either X-Wing gear or his cut scene duds. Sure, maybe no one else wants him, but he'd be pretty darn cool.
Han Solo in bespin gear/jacket. Sure, there's a pretty good one out there with POTJ Bespin Capture Han, but he's not "super articulated" at all and the head is a mediocre likeness. We have (okay, I don't own one... yet) a great ANH Han and an awesome ROTJ Han on the way, and this would really complete it I think.
For that matter, I think a lot of people would love to see a VTSC Han Solo Hoth Outfit- erm, Hoth Battle Gear figure. The Saga figure reeks of 1995ish and has a likeness resembling Chevy Chase, although it's not truly a bad figure... but Hoth Han is a well-loved classic and deserving of the VTSC treatment.
On that note, I'd like to see a VTSC Hoth Luke, but that's just me <3
Luke Skywalker in Bespin Fatigues is another likely choice. The Saga figure is great, but I'd love to see a truly SA version with a lightsaber that could attach to his belt (and just think, that itself would be a vintage throwback, since it would be the first Luke Bespin figure that had one since then) and a more general-purpose face.
A new VOTC C3PO that's a real C3PO, with bending knees and swivel elbows and removeable limbs! Not to mention a good likeness and vacuum-metallized paint.
I don't really lust for a SA Snowtrooper, but it's high time for one. The TSC kitbash = lame.
SA Lando in Han Solo's clo-, um, Smuggler Gear. Maybe he only had one scene, but you all know you want him! Think how multi-purpose this figure would be! He would be the height of awesomeness.
SA Luke Skywalker Jedi Knight, preferably with removeable cloth robes so he could also be Death Star II Luke. Or heck- throw in the poncho and helmet, too, and a removeable right hand (one gloved, one not) and you've got a Luke that covers all but one scene of ROTJ...
Maybe he's boring, but I would need him. Need him I tell you! Saga Jabba's Palace Luke is cool but far from "ultimate."
Endor Leia with softgoods is an awesome idea. I'd definately buy one.
SA General Lando. Again, the saga figure is good, but better could be achieved.
SA Admiral Ackbar. He could be a pegwarmer for a VTSC figure, but I'd like to see a new one that could sit and gesture and cross his arms and do all that good stuff.