I wouldn't mind seeing a new version of the original System Shock from 1994. Playing it now, the graphics and the controls are rather outdated.
Actually, new versions of System Shock 2, Thief and Thief II would be nice too as the game engine would have to be upgraded to run properly on modern PC hardware which can be a bit tricky now as the games doesn't like multiple cores and some other niggles.
This would be my answer exactly. I would add only the original
Tie-Fighter (and related: X-Wing, and X-Wing Vs. Tie-Fighter, and X-Wing Vs. Tie-Fighter: Balance of Power) by LucasArts. Those games were awesome. I wouldn't mind a new Star-Wars game that was
only space-combat.