While not 100% official, the below tweet by Scott Derrickson along with reports that the director of such movies as The Day the Earth Stood Still, The Exorcism of Emily Rose, Sinister and Hellraiser: Inferno is being touted as Marvel’s pick seem to suggest that this is very close to being a done deal.
Looking at Derrickson’s past movies may just give us an idea of what Marvel has in mind for the feel of the Doctor Strange movie/s. We may just be looking at the dark side of the Marvel Cinematic Universe very soon.
Action Movie Fanatix 
Sounds like they’re going for a kind of horror approach. Strange. (did you see what I did there?!)
…yeah… I saw… 🙂