Originally Posted by Blackman
maybe because Doctor Strange fits better into their Phase III plans similar to how GOTG fits with Phase II better than a BP film would
Maybe. With Doctor Strange and Ant-Man, you open up the MCU to two unique corners of the universe--the world of magic and possibly the Microverse. Also, in response to MessiahDecoy, be sure not to limit the vision of the MCU as Avengers-only. Sure, the culmination of Phase III could be an Avengers sequel, but if they open up the MCU enough, we could see Phase III culminate to an even bigger storyline, beyond just the Avengers.
As for Black Panther, Wakanda is also a unique corner of the MCU, so let's not count it out until they announce otherwise. And who knows? Maybe Cap 3 will take place in Wakanda.