I for one think that he has the personal attributes required to captain this great club. Our last 5 captains, Bryan Robson, Steve Bruce, Eric Cantona, Roy Keane and Gary Neville, have all been tough and loyal players, and Vidic would certainly fit in well with those names.
Vidic has worn the captain's armband before at United, and he was captain at Red Star Belgrade for 3 years. The experience of leading the team is certainly there.
Whilst it is unlikely, given the fact that there are many possibilities for the role, Vidic is most definately worthy of consideration when it comes time to choose the next captain of this great club.