Doctor Strange, directed by Scott Derrickson, has several promising features but each of them is held back by some accompanying flaws. Starting with the main character, I thought Stephen Strange had a fairly good arc moving from self-involvement to selflessness and Benedict Cumberbatch turned in a good performance. But that arc was a bit too obvious and cliche for my taste, and the film also suffered because I don't think any of the other characters had enough development or multi-dimensionality. It felt to me like everyone else was there to serve Strange's story -- and yes, this is his solo movie, but it is still possible to give the secondary characters some of their own development and nuance and I felt like Doctor Strange was underwhelming in this department.
Many people are praising the visual effects, and while I agree there are some elements that are visually stunning, I felt like the land/building warps were usually pointless and only served to create an interesting backdrop to the action. There were a couple scenes where the land warps were used by a character to try to trip or stop another character, so that is at least minor purpose, but that still seems like an inefficient way to stop them if you have magic at your disposal, and most of the other times I couldn't discern any real purpose for all the visual craziness that was happening on the screen.
The blockbuster movie formula was in full effect, especially at the beginning. This is neither a good thing nor a bad thing, necessarily -- the formula is effective for allowing general audiences to immediately plug right in to the film and map it onto familiar mental structures for how to process and enjoy this form of entertainment, but the formula may also be less engaging for moveigoers who seek more challenging fare or who enjoy the challenge of trying to follow something that is a bit more unique in its structure. (I should clarify that I'm referring not to a Marvel movie formula but to a general, Save-the-Cat movie formula, which Marvel uses often but it's not specific to Marvel.) Doctor Strange opens like so many other movies with a dark scene that introduces a villain and a macguffin, and before the scene even ends we know that we will move on next to meet our main character and then in 20-30 minutes the villain/macguffin from the opening scene will cross paths with the main character and set the plot in motion. (The Suicide Squad novelization has precisely this formulaic opening but the final version of the film avoided it by starting with some of the squad members and bringing in the Enchantress and her brother a bit later.) After that formulaic villain opening, we go to the next part of the formula: meet the hero in his current status quo and hit us over the head with his main personality characteristic / character flaw. Then, after about 12 minutes, throw a big wrench into the main character's life, setting up the plot and an eventual resolution to the character flaw. (For more on this formula, including time estimates for when key events will usually happen, see http://www.savethecat.com/.)
For me personally, recognizing the formula takes me a bit out of the movie rather than drawing me in along its well-trodden flow. But I recognize that that's a matter of personal taste.
I was not especially impressed with the villain -- to me he basically always seemed to be an actor in makeup, I never got totally absorbed or lost into him as a threat. And I also thought the music missed the mark in several scenes. Sometimes, though, I think this was the director's fault and not the composer's. For example, there's an early scene with Stephen Strange still working as a surgeon when the director seemed to have told his editors and composer to fill the scene with tension around whether the surgery would be successful or not. That tension did not work for me at all because they had already established what a great surgeon he was and this part of the formula is intended to show his status quo, which is as an arrogant but highly skilled surgeon. So of course the surgery was going to be successful. No tension to be had and it just seemed futile to me that they were trying to force the tension into the scene. A better choice, I think, would've been to simply emphasize his surgical brilliance and the reactions from the others around him who are highly impressed, which could then be contrasted with his later struggles and those around him who have much more developed skills with magic. There were other scenes like this one where I felt as though the filmmakers were trying to force a certain feeling onto me that did not actually fit with what I was taking out of the scene. This might be a problem with how I was viewing it, but nevertheless the filmmakers and I were not on the same page in several spots.
The last thing I can say without getting into spoilers is that I thought the humor was really hit-and-miss. There were a few good lines that were funny, and I think Strange's arrogance and sarcasm is a good source of humor that was fairly organic to the characters, but there were also many spots where I thought the forced inclusion of humor worked against the film. I noticed at least 4 different places where the movie was pretty successfully moving me toward a real feeling of fear or sadness or suspense, but they would ruin it by putting in a joke or a sight gag amidst the seriousness or tension. I know they were probably trying to cut the tension with the humor -- and yes, sometimes things can be extra funny because they allow us to release the built up anxiety or sadness, but to me these moments seemed like they ruined the tension or sadness rather than punctuating it. Granted, it's a fine line, but again I did not seem to be on the same page as the filmmakers.
P.S. I like Tilda Swinton as an actor but I think they should've kept the Ancient One as having Asian heritage.