The fundamental problem with Doctor Strange is that it's not about anything.
Marvel's latest Cinematic Universe hero bears some surface-level similarities to their first: 2008's Iron Man also starred a wealthy genius with a predilection for stylish facial hair, whose ego was challenged by an unexpected set of circumstances that challenged their existing view of the world and their place in it. But while Tony Stark's wake-up call was entirely of his own making - a result of years, if not decades, of indifference to the people who bought his company's weapons - Stephen Strange is thrust into his new reality entirely accidentally.
Even Ant-Man had Scott Lang's choices drag him into the story - he's an active participant, and it has the added subplot about what a person can be willing to do - or sacrifice - for their family. But Stephen Strange is just a spectator.
The car crash that ruins his hands is arguably his fault, but a momentary distraction when driving doesn't illustrate any kind of major character flaw or inner conflict that Strange has to overcome. It doesn't turn out to have been an unintended side-effect (or deliberate outcome) of any other characters' actions. It's just a meaningless, random event.
Strange also has nothing to do with Kaecilius' plans - in fact, it feels like no other character does. We're given the sketch of backstory (a history shared with Kung Fu Panda's Tai Lung), but there's no plan to stop him. The Ancient One doesn't even seem particularly bothered about looking for Kaecilius - she just replaces the librarian and moves on. There isn't even any indication that the three Sanctums have had their defences bolstered. Kaecilius is just left to his own devices until Stephen Strange stumbles - again, accidentally - into his way, and manages to deus ex pallium his way out of the confrontation.
The plot clips along at a JJ Abrams-esque pace, hoping we don't notice. It's all forward momentum and no breathing room - but there's never a sense of how much time has passed between scenes. When Strange stumbles into Christine's ER, there's no telling whether it's been years, months or just a couple weeks since they last saw each other. How long has he spent learning the mystic arts? No film has ever needed a training montage more than Doctor Strange.
Benedict Cumberbatch is at his Cumberbatchiest as Stephen Strange, and despite his Dr Gregory House accent even manages to find the time to act in a couple of scenes. Tilda Swinton somehow knocks her role out of the park, saved from her character's lack of depth by some great dialogue - a crutch which, sadly, isn't afforded to Mads Mikkelsen or Chiwetel Ejiofor. These are two of the most charming, talented actors on the planet, relegated to cardboard cutouts with barely a motivation between them; that they manage to turn in memorable performances at all is a testament to their abilities.
The visuals vary wildly; I'm not a fan of the acid-trip design of the "Dark Dimension" (not to be confused with Thor 2's Dark World), but there's no denying it's a unique look for the MCU so far. But scene geography is almost always disastrously muddied by the camera during fights - and that's even before they start messing around with Euclidean space. The kaleidoscope effect that twists reality would have a lot more impact if it was a location we had the measure of, but there's never a chance to get your bearings before the fighting breaks out. (This isn't helped by the television-esque way everything is shot; there's a lot of mid-closeup during dialogue with a single character on screen, which limits your view of the rooms they're in.)
I've been trying to figure out where Doctor Strange sits in my MCU rankings, but I can't place it. I almost convinced myself that it's better than The Dark World, but at least that had Loki and ended with that great dimension-hopping final battle.
It's probably better than Iron Man 2.