Really? As someone who read a lot of the reviews for that movie when it came out very rarely did reviewers mention the ethnicity of Johnny Storm, and even if they did, it wasn't as a knock exactly. There was plenty the movie going against it but casting a black Human Torch wasn't one of them.
The backlash at best was mostly limited to online, really. There was no mainstream audience backlash at all. You're overstating.
Wrong. Being more iconic does not equal being more popular. Superman is more iconic than Spider-Man but that doesn't mean he's more popular. As for your point about anybody can easily recognize the FF --the FF are losing that. This is anecdotal but just recently I played a game called "Guess that Superhero' with a couple of very young children who love the MCU using
this.
And guess what: When I asked them to guess who any of the FF are characters are none of them could answer. They didn't know who they were. and they correctly named almost every other superhero on this. That's quite telling.
It's a shame that being more recognized doesn't always equal to being more liked or preferred by the audience as a whole. FF being more well-known doesn't equate to them being more well-liked by the mainstream as a whole. Which is exactly what Crimz is getting at. If anything, thanks to those horrible films & lack of good media portrayals the FF brand is severely tarnished enough that I don't think most people who don't read comics or visit forums would care at all about a race-swap.
Look, I would like the FF to be cast as racially accurate as much as the next guy but the fact of the matter is I think Marvel shouldn't feel beholden to cast that way if they felt a person of color better personified that character than most white actors could. So what I'm getting at is that race-swapping won't effect the MCU Fantastic in either a negative or good way. . What will effect it will be how good the film is, not the actors skin color who's cast.