I'm taking a different slant:
Take Newey's Red Bull. Any of these drivers could dominate in it, assuming a true #2 alongside him (in VERY ROUGHLY descending order):
Vettel
Hamilton
Alonso
Kimi
Webber
Kubica
Massa
Schumacher
Rosberg
So for me, the more important consideration and the more interesting set of changes will be in the teams' technical makeup. Will teams try to steal Newey? (Not likely) Find the hitherto unknown "new Newey"? (Unlikely) Do a bit of poaching? (Quite likely)
Where will Paddy Lowe end up? Will Force India's tech team implode? Will McLaren feel they need new blood to turn things around? I can see Ferrari resuming their attempt to get Giorgio Ascanelli from STR (Why?)
So, for those of you closer to the action than me, pass on any rumors about movement on the tech side.