You find it believable that even in the marvel-verse, that a 16 year old girl, is the Minister of Technology? Is smarter than Bruce freaking BANNER?
A shit movie.
Um, that's not all that abnormal for Marvel at all. Genius characters that can create and understand all sorts of crazy stuff are all over the place. Besides Shuri, you have characters like Amadeous Cho, Moon Girl, Valeria Richards...Marvel has long used the idea that some people are ridiculously intelligent as an easy way to pass off any kind of technology they want. They do it with children, too.
The movies have a lot of canon to try to deal with. Superscience has long been a superpower. Generally there is an explanation for it. None was given for Shuri. And even allowing for that, they were over the top with it.
Your example of Spiderman, was a good one. THe difference in the way they dealt with the interactions between an older and massively accomplished superhero, and a young but bright and relevant character, really showed the difference between doing it right and not.
What explanation was given for Tony Stark's superscience? How about Bruce Banner's? Hank Pym's? The only explanation is they are all geniuses and therefor any technology they want to give those characters is to be accepted. I'm not sure how that's different with Shuri.
Also, what specifically is over the top about Shuri, as opposed to the other such characters Marvel has used in the movies?
Correct. Tony Stark's super science requires a suspension of disbelief. You need an additional suspension of disbelief, that the answer to so many problems, ie build an army of Iron Men, is never done.
Bruce Banner's super science requires some suspension of disbelief, though his super science is not that super, and it is very believable that they don't want to do that to more people.
Hank Pym's super science requires suspension of disbelief. His accomplishments, seem less world saving than Starks, so the lack of an army of Ant Men, seems more believable.
Shuri's super science requires a suspension of disbelief. THat she is super science, at age 16 as opposed to the other Mad Scientists listed, who mastered their fields as adults, requires another suspension of disbelief. That her brother is a super hero, requires another suspension of disbelief. That her family maintained secrecy of hiding a secret the size of a nation, for centuries, requires another suspension of disbelief. Vibranium, requires another suspension of disbelief. That a nation ruled by a warrior king with a warrior culture, and a massive tech advantage, never waged war, for centuries, requires another suspension of disbelief. The cloaking field, requires another suspension of disbelief.
Seven is a lot more than one or two. That is what is over the top about Black Panther.