To me it suffered from the same phenomenon as Creed in that the main character who we should be caring about (Adonis Creed in Creed and Rooster in Top Gun: Maverick) wasn't the star
Maverick's story is already told and there's really nowhere else to go for his character development as someone over 50 years old in the twilight of his career, thus focusing on him in the sequel leads to bland writing. His role should have been similar in scope to Viper's in the original.
Forgetting (and forgiving) the ridiculousness of the overall plot for a moment, it seems the weakest part of the script was actually pointed out by Jon Hamm. Maverick spent 2 weeks (and a lot of screen time) showing his students that they couldn't do the mission. Yes, the scene where Maverick then goes out and shows everyone it
can be done is meant to address his weakness as an instructor, but that was lazy writing and in the end, he didn't actually have them go do it as a team until the actual mission. It was kind of a "what was the point of that?" moment for me.
Not only that, they were cast as no-name, relatively bad actors.
I'll give the actors some slack when trying to portray military bravado when they have no experience or foundation to understand how it actually happens in a room with peers. To me, it seemed a big reason Cruise can pull it off now is a lot of life experience and realization of self-worth. Hollywood in general excels at getting this wrong (especially for aviators)
Generation Kill seemed to do it pretty well and is an exception.
And don't be talking bad about sweet little Monica Barbaro.