If (IF) you went down, you would probably only lose players that you wanted to lose and look to rebuild.
I guess the ones at threat that you wouldn't want to lose would be Medel, Caulker and Marshall - I certainly wouldn't see Marshall pushing to leave, and you may be blessed by the fact that he isn't showy or name enough for lazy scouts to turn to (and no world cup!).
Caulker would prob gain a lot from dropping down and popping back up (although I would love him for us). Medel you may lose, much like we would lose Michu and Bony, because he is a) very good, b) being showcased in the World cup, c) career minded and used to playing in the top division.
You'd see the new Norwegian lads find their feet too - the Championship is a tough league for pace but their technique would help them out. What you'd probably find is, as mentioned above, a bit of work on leadership throughout the team. Bellamy would be fine back in the Championship and would prob stick around (I mean, not retire) so that he could help you bounce back. Bellamy and Campbell would eat up the championship anyway.
You'd have Hudson to (I'd assume) partner Caulker, then you could work on fullbacks that could build and prepare for the Prem. An experienced holding mid (maybe a last hurrah for Scott Parker?) and a winger. You'd prob find a lot of joy, and I would say the same should we go down, going through lower champ and league one sides for the future Lamberts and Lallanas rather than too many big-time players.
If you stay up, obviously, there'll be a chance for Ole to really get to coaching the team and get some more players that support his style.