Since I only collect OT-era Imperials, I can only offer my opinions on those chars, but... some I'd like to see are:
1) Death Star Commander - Yes! A very needed character who would be easy to make
2) I second the red Stormies, although I know alot of purists will hate them. I think they are cool and I'm sure they'd sell strongly.
3) The gray Imperial technician idea above is a good one, although the arms of the "Imperial Officer" figure are so limited and awful. Perhaps use differenly jointed arms so they can straighten out?
4) My biggest want, however is...
A repaint of the excellent ROTS Red Guard, to make a new RotJ Royal Guard! His sculpt is superb, in fact one of the best Hasbro has ever made, period. Give him black gloves and more red/black armor rather than the purple (or just use Kir Kanos if Hasbro is REALLY lazy), and use the nicer robe material from the TFU Shadow Guard, but red. Also a force pike (from an older figure) instead of the gun. This would be an unbeatable figure. For bonus points make the robe removable so he could be in a sort of "battle-ready" situation if desired.
I'd like to see more Imperial EU if possible, and this might be attainable through this wave.