Ridley Scott, or maybe a director who's good enough on handling ensemble stories. And who's a fan of X-men.
When I watched The Italian Job, I thought the director Gary Gray really managed an ensemble cast greatly, giving everyone time to shine. And he also nailed the action wonderfully, giving a great tone to the remake.
Another one I can think of is Paul Haggis, director of Crash. He also did great with the ensemble cast. I don't know if he can do good action, but since he wrote Casino Royale, maybe he can.
The dream situation would be having Singer back, but hey, it's Impossible.