These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: The Falcon
Broken Base: Him becoming the new Captain America has resulted in a split in the fandom. Some are happy as Sam is the only person alive currently that Steve would trust to take up the mantle (Bucky is currently Faking the Dead so he's not an option), but others would prefer if he just got a similar push in his usual identity rather than needing a 'promotion'. Then there's those who, rightfully or not, accuse it of just being a headline grabber, or those who are against the idea of him taking the mantle just because he's black. There's also the fact that a lot of the people complaining about it conveniently forget how awesome Bucky!Cap was.
Fanon Discontinuity: Most fans would rather not have the Falcon being Retconed from a social worker into a former pimp as official canon.
Same with the writers, it hardly gets mentioned at all these days. Anthony Mackie was also glad to have it ignored in his film counterpart's backstory.
Fridge Brilliance: Sam becoming Captain America may be controversial, but who else would Steve trust with the mantle? Bucky's Faking the Dead and not an option as putting him in the spotlight again would expose this ruse and risk the Russians demanding he be handed over, while the only other person Steve would trust with such a responsibility being Sharon Carter, who's currently dead. Sam is the only man Steve could trust with such a task as being Captain America.
Falcon's movie duds are a case of Movie Superheroes Wear Black, despite Mackie's wish to wear the classic red and white outfit, but Falcon didn't wear those colours for some time in the comics. So, while he's not wearing red yet, its very likely he'll switch to the 'right' colours eventually.