Obviously I don’t think he will move as I think he’s pretty comfortable where he is right now in a competitive car and team but let’s pretend Hamilton DID move to Red Bull, replacing Webber. Who would replace him and become Button’s teammate?
I’d imagine that if Hamilton replaced Webber, Webber would probably retire so I don’t think it’d be a straight swap.
I would think the obvious target would be Vettel, but he’s not going anywhere yet.
The next obvious target would be Rosberg and I would see it happening. After all, he wasn’t scared of taking on Button when he signed with Mercedes (bet that was a shock when Schumacher came in instead!)
I don’t think they would take di Resta yet, McLaren need someone who will be fighting for the championship. Maybe when Button himself retires.
We must remember that Button is a championship winning driver, so he doesn’t necessarily need a ‘superstar’ teammate.
Schumacher might be an option (imagine that..!). As would Rosberg (although i doubt it, as I think he has a long future at Mercedes). Kubica would be a gamble – and many think that Ferrari is his ultimate destination.
More realistically though, I could see Glock, Hulkenberg or Di Resta moving there. As mentioned, Button is a proven race winner. He may not be massively rated by everyone here, but he’s certainly good enough to lead the team on his own while a younger driver is trained up to be a title contender in the future.
I think the queue at McLaren for drivers filling a seat opening would look like: Hulk, Nico, Di Resta.
We assume that McLaren have learnt from pairing two superstars with strong personalities together. I think Heikki was their weakest selection of the past ~20 years and they might not do that again either.
I would probably take Sutil if Hamilton did move. He has enough experience to back up button and possibly challenge him. It would good to see Sutil in a top car. Hamilton and Vettel in the same team would be an intriguing line up for Red Bull.