SPOILER WARNING
Overall, this has probably been one of the most disappointing of all the MCU movies for me. What makes it so bad for me is how it feels like they completely forgot about all the things that made DS1 so good.
First off, the character development is nonexistent. Doctor Strange doesn't really get any interesting screen time either, which wouldn't be so bad if the rest of the characters weren't as uninteresting as they were.
The worst part of the movie for me, however, was that it had potential. I was ecstatic to hear about it, as Doctor Strange is one of my favorite characters in the MCU due to Benedict Cumberbatch being one of the best actors left in the MCU cast.
More about this movie having potential, though, is that it doesn't even have the problem that most MCU movies suffer from. Most MCU movies try to keep escelating the stakes to where there isnt any real chance of the villan winning in any respect. DSMM was the first MCU movie in awhile that genuinely had the potential for the heros to lose.
And clearly, some heros lost. This is controversial, but I really enjoyed the few scenes with the Illuminati that we got. It definitely could have been better, and I feel like they should have gotten more screentime with them before they died. But I like that they died, and that it was so brutal. I remember being audibly shocked when they got torn through so easily, which is a feeling the MCU hasn't really given yet.
If they had kept up this high stakes, no-one-is-safe vibe throughout, then I feel like this movie might have actually been good. And if im being honest, it would likely have been better to put an evil Strange or something as the main villan, and almost, if not fully, cut Wanda from the movie. I won't get into the problems with her, as I'm sure multiple people have already.
The plot that we got was nonexistent, with obvious story dumps throughout, and additions of unnecessary characters for little to no reason.
TLDR: Movie was disappointing, had potential but ultimately flopped due to poor handling of story and characters.