The majority of modern film protagonists are just that: characters, strong or otherwise; and they result from a top down, structurally dictated approach to screenwriting. They're sketches animating flesh. They're a collection of traits wrapped around a couple of driving goals which tend to shift around the mid-point of a screenplay because that's what the books tell the development people to tell the writers to do.
Good writers don't write characters, they write people. They don't write plot, they write stories in which people interact and out of which plot arises naturally, like the subtle shifting patterns of a forest arise naturally from the interaction of thousands of trees or the calligraphy of sand dunes emerges from the interplay of wind and sand.
Critiquing Marvel blockbusters for lack of profundity in protagonists doesn't provide much of a challenge. The muscular male slabs smashing bits of New York into each other in an externalisation of their inner struggle are just as reducible and risible as the female ciphers.
These characters have to be cartoonesque because they have to stand out in the foreground against the increasingly noisome and cartoonesque background of world salvation that drives modern box office blockbusters.
When screenwriters write people, rather than human plot devices, they become nuanced and interesting, whether they are strong or weak. troubled or at peace. That's harder to do when one has to justify 400 million in production and promotion.
A good article, though!