If Ultron ends up being made of Vibranium it will eventually lead to this guy as part of Phase 3:
Cap's Shield, Falcon's Wings, and maybe Ultron made of Vibranium? And the possibility of some of the Avengers going to Wakanda to retrieve the Vibranium?
Yeah, he'll get his own movie. Can't have the Avengers going to Wakanda and not have their king.
If a Black actor has been cast in this film and he's not Ultron and signs a multi film contract, then we know who it is going to be, especially if part of the plot calls for SW and QS to go to Wakanda to retrieve some more Vibranium.