Heh, just saw this one so I guess I'm chiming in a little late.
Honestly, I've been wondering about this one, and I have no idea. I really don't know what Alonso is trying to accomplish (other than money) with going to McLaren. This is much different than Schumacher went to Ferrari, and it still took them quite awhile to get it all together and start winning championships.
I can't see how the Renault won't still be a competitive car, but do I think they can win much with those drivers? Not really. It would have been more interesting to me had they gotten Kubica. ... I guess they do have to deal with switching to Bridgestone though, so perhaps all the former Michelin teams will be at a bit of a disadvantage at the start of the season...
In the end, Raikkonen seems to be as good a choice as any if he can get a little (good) luck for once. Quite a shakeup at Ferrari though, I could definately see them dropping off a little.
-Tyrion