Just rewatched Doctor Strange as I'm in an MCU mood before I see IW tomorrow, and I hadn't seen it since the cinema. It remains highly enjoyable and I feel it gets too much of a bad rap.
There's some fundamental issues, which is that it's in Phase 3 where the MCU is really branching out in style and breaking away from the basic formula it had established, but sticks to a familiar formula nonetheless. In that regard, it feels like it should have been released in Phase 2. Like Thor 1, they play it safe for narrative and character in order to ease in a much bigger and more out there concept of magic and dimensions, with which they can go crazy in future films. It follows the Iron Man 1 story, has a fairly perfunctory villain, no major genre shifts, etc.
However, GOTG 1 is also an origin story, but it just went all in on its cosmic comedy adventure, and it worked. So I think them holding back was unnecessary, audiences can take it. Of course that film also had a perfunctory villain, but hey it was an origin story for a whole team, not one dude.
All that aside, it is a really well made film. It could have done with being longer, perhaps with more time spent with Strange pre-accident, and more on his training, but it's still nicely paced and the production is excellent. The visuals do go all in and are fantastic (along with some choice cinematography and costume design). While some of the cast are wasted (like McAdams and Mikkelsen), it is a great cast, and the musical score stood out on the rewatch as being really rather good, with fine use of choir and harpsichord. Kaecilius is a starter villain through and through (and Marvel know it, they didn't use such a minor and obscure villain by accident), but he's saved from being Malekith tier by giving him a strong scene where he actually explains his motivations, which make sense. I also give the film credit for having a very creative climax.
So in short it's a really strong, if tentative start for Strange, but it's very clear the real meat will be in sequels where they can truly go off the walls. Scott Derrickson was a curious choice given he'd only made horror films, and not particularly good ones at that (in fact Doctor Strange is his first critically successful film), but reading interviews, he obviously has a genuine passion for the material and that counts for a lot. Amidst the ambition of Civil War and Black Panther, the creativity of Ragnarok and GOTG, etc, it does feel quite safe, but it's extremely well made safe and that's ok.
A good foundation.