And I would call not dealing with actually developing your core romantic relationship in any kind of real way as a flaw. It is a flaw when you are telling a story and development happens that isn't really explained.
And again, for the third time, I'm cool with it as is. It's not a big deal. But, having a few scenes or moments showing people bonding or why, as characters they are into each other is too much to ask. And everything has been done here countless times before. Hero out of his element, relevant hero, crazy bad guy who feels neglected, etc. That doesn't mean trying to give some substance is a bad thing.
But, I'm done addressing this. I'm just repeating myself here.
If anything, this movie does make me think about who will step up and fill these empty voids. I think it will be someone we don't know or know much about. Captain Marvel and Black Panther, for example, will be great core members but I don't think either one of them would want to be the head of the avengers. They have communities they are more worried about.