The thread title is jumping the gun. Cruise is simply in talks about the possibility of starring in the remake. It's not definite yet.
I've just begun watching The Man from U.N.C.L.E.
via Netflix, and I think Cruise would be an inappropriate choice for Solo. He's good at what he does -- whatever personal idiosyncrasies he has, he's a solid, professional actor -- but he's not a good fit to this character and franchise. The series had a light, humorous tone (increasingly campy as it went on), and Robert Vaughn's Napoleon Solo was a playful, theatrical, almost impish sort who treated the spy business as a game. Cruise might be better at playing Illya Kuryakin, who was a more serious, distant, enigmatic sort -- although Illya was also a younger man and a major sex symbol, dubbed "the blond Beatle" by the media due to his popularity with young female viewers.