If WandaVision is somehow a set-up for the arc Disassembled where Wanda goes crazy after losting her childrens, Multiverse of Madness could be an event movie, but even if it's not, it already has the concept of multiverse that can already open the door for many possibilities.
Yep, but it seems this movie is going to have a lot of characters, and it all indicates that Nightmare is going to be the villain, so i thought they would save Mordo for the third movie.
It seems that his departure was because he wanted more time to work on the movie and Marvel didn't want to delay it because it's all already scheduled. The Russos shot back to back Infinity War and Endgame, the first Doctor Strange was released on 2016... Well it must be Scott was not putting a lot of effort in the movie, because 6 years for a solo movie is enough to make a movie.