I believe this is where the disconnect is taking place. The Johnny Storm version of The Human Torch has a history going back to 1961, 1939 if you include the similar looking Jim Hammond. For iconic characters, such as a key member of Timely's Big Three and Marvel's First Family, tradition is everything.
Storm and Hammond are different characters so I don't think Hammond should be mentioned at all.
And when has Marvel ever stuck to tradition when it comes to the movies? The X-Men didn't wear their traditional uniforms. The FF movies didn't stick the comics either. Neither does Marvel Studios movies and they've been successful. So has some of X-Men's movies.
Film is a different medium. The FF movie is an adaptation, not an exact translation of the comics. Name one Marvel movie who's story and characters were exactly like the comics?
Comics are a visual medium, which is why fans get giddy when we see RDJ, Henry Cavill and Chris Hemsworth sporting a "leapt off of the comic book page" appearance while in full costume. We've already seen Johnny Storm countless times through the decades, and due to the nature of his powers Johnny spends only a fraction of his time in comics or on screen fully alflame. Given the fact that Spider-man is fully masked, I was actually onboard the Donald Glover as Peter Parker bandwagon. I was a fan of his work on Community and felt he would fit seemlessly into the role. A racial recast of Johnny Storm not only changes his iconic appearance, it also requires an alteration in the relationship to his genetic sibling. That may not matter to you, but to others it appears as though Trank is considering making unnecessary changes to beloved characters.
What makes Donald Glover as Spider-Man okay and Johnny Storm not? Spider-Man is masked, but Johnny Storm is on fire. 
It alters his relationship with Sue, but that could be easily explainable. It's not like they have to have close DNA to get their powers. They're not mutants. It could even open up new stories for this new interpretation.
A hefty Sue may be a problem for you, while a black Johnny may not coincide with my vision for the character. Both opinions are equally valid.