'Peels off the Iron Man labels from the generic action doll, replaces it with a Dr. Strange label.'
There is certainly a sense in which Iron Man / Tony Stark has no character.
I think he does have character. He is (or at least becomes) a man driven by guilt (Stark Industries' militarism; the loss of Peter Parker) and regret (his relationship with his father), both of which lead to an overdeveloped and overwhelming sense of personal responsibility (his various attempts to 'protect the planet'). And from this comes a profound death wish.
On top of that, he's very funny, charismatic and frequently insufferable. And let's not forget the PTSD.
(Admittedly, Stark has the advantage of appearing in more movies.)
When a Marvel movie attempts to imbue emotion into an interaction between Banner and Romanoff it's devoid of any heft because (and this is really core to the nature of never-ending comic characters) they don't actually have any character - just a costume or a power or an ability. They're utilitarian creatures. Mannequins. A world of walking MacGuffins.
Romanoff's backstory and hence much of her character wasn't really revealed until Black Widow. Half of that is a bit of a cliché, but the family angle is interesting. Like Stark, she's another person motivated by guilt, and personally I find characters driven to redeem themselves inherently interesting.
As for the Banner/Romanoff relationship, I do think you have half a point - it could have done with a movie of its own to explore it. However, the interest for me is the fact we have two obviously lonely people, both of whom have learnt to push down on their emotions.
One could argue that a lot of this is verging on the subliminal, but I find it's there. I think it's one of the reasons that the Marvel movies work better than, say, Star Wars I-III. I don't recall feeling any tears in my eyes during the latter, but quite a few during the Marvels (one or two during The Mandalorian, though).
Regards,
Robin
