An FPS with the graphical style of Chaos Engine would be interesting to see... still I wouldn't like to see Chaos Engine as an FPS.
UFO got at least 2 sequels, AFAIK, both for PC. Maybe there are even more sequels.
I personally think most classics should be where they are. Don't touch them, they are classics for a reason, and they don't need any "update". Most games I love are just TOO DAMN GOOD , and they don't have any room for "enhacements". Yes, you can probably make their gfx better, but this makes no difference to the gameplay.
But yet, I can mention a game I would like to see brought to the new millenium: Stunts (or 4D Sports Drive , as you wish). Better graphics, more cars, a more flexible track editor (Athoulgh the track editor is already VERY flexible), better A.I. , more cars on track, more stunts, and a multiplayer mode would make this THE racing game to finish all other racing games.