The reshoots are typically for continuity with future projects. For bad test screenings I think usually you see major edits like with the Marvels to just speed up the movie or streamline it to simplify the plot. My guess is most of this movie was shot before the RDJ/Doom change up for the Secret Wars movies. They surely have continuity issues even with smaller plot points that have to be reshot. Yeah this movie could still be hot garbage in early screeners but I don’t really think a producer and studio executes would think you could just add or reshoot a scene or two and that’ll completely change the fundamentals of the movie. The main issue the MCU has is they don’t just pull from the best scripts that the best writers create from an artistically inspired journey. What they do is the main producers look at puzzle pieces they have to play with in terms of characters. Look at who they want to interact with who. And then before they cast or write a script, task the GCI staff to go ahead and work on the big action set pieces ahead of shooting. That way they can shoot the movie with actors in scenes already shot in cgi, and let the director and writers fill in the blanks with character and dialog that’ll get them from point A to B. This formula has served them well in the past at times. Especially when they wanted to put out 5 movies a year. But in that formula you also are inevitably going to had major duds. If you waited for great scripts from creatives then you run the risk of having a bunch of movies that have nothing to do with each other and never having the characters you want to play with each other get in the same storyline.
I miss street level threats. I'll even take city threats. Not every movie needs to be an existential crisis for the universe.
Looking at reviews: good action, thin plot. That could go either way. John Wick was great action, paper thin plot. If I get 50% of John Wick and it moves the MCU plot along, I’ll be happy.