It's a decent chance for an upgrade. Derrickson obviously was passionate about the material (the story of his pitch to direct it attests to that), had a decent handle on the weirdness of visuals (if aping Inception hard), but he's a very middle of the road director regardless. There's no spark there as the likes of Coogler, Gunn or Taika have. Doctor Strange had lots of excellent elements, like casting, costume and production design, visual effects, but never quite rose above "solid familiar origin story". Maybe freed from those constraints and with a little more of his horror background allowed, he would have delivered a superior sequel, but that's irrelevant now, I hope they've got someone exciting lined up.