Well, I suppose they could do a story out of the Avengers/Defenders war if they do launch Doctor Strange.
Black Panther should be introduced in a Fantastic Four reboot if he's going to show up at all. Truthfully, I'd kind of appreciate it if they didn't use that character on the big screen for a while after the train wreck that was the whole "Black Panther" cartoon (which I saw on Netflix), which at times seemed like more of an attempt to mock other super heroes and white society in general than anything else, and truthfully with the current politics I don't think anyone can handle the character in the larger arena of media, especially if BET still holds the rights.
Black Panther was originally a pretty cool character, sort of like Batman, his big gimmick for a while was that he managed to take down The Fantastic Four with traps as a personal test for himself to prove he could beat superhumans, before losing to Wyatt Wingfoot, who had no powers and was flying their jet to Wakanda at the time. After which he kind of apologized and went on to be a more straightforward super hero, even if he did have his priority in defending his own kingdom, which also explained why he wasn't always around, and also provided a plot hook to get other characters involved to show up and give him a hand.
Having seen where the character has gone since, I more or less don't trust the current creators out there to cover the material without derailing the entire thing with what amounts to racial one upsmanship and using the character as a focus for political rants... which are things I watch movies to get away from.
At any rate, if I was Marvel right now, given the fate of the X-men franchise, I could see them using Doctor Strange and a few other hero movies to launch The Defenders, and if they can juggle it all having the two teams of heroes blow the crap out of each other before realizing they all got played and teaming up to take down the bad guys.
For those that don't know, The Defenders was a team lead by Doctor Strange to defend earth against otherdimensional/mystical threats. The original idea is that where teams like The Avengers or X-men were handling the regular super villains, science-criminals, and similar garbage, The Defenders were preventing things like Dormammamu or Null The Living Darkness from coming into earth in the meantime and wtfpwning everyone. In the scheme of things it didn't last very long, but it was a cool idea at the time. Something that I wish that had done more with, much like the Iron Man led "Force Works" team.
