Why is he settling for a small role in Black Panther?

Who says it's a small role? He could easily become a recurring character throughout the Black Panther and Marvel series if they like him enough.

"Lives with no meaning go straight past you, like trains that don’t stop at your station."

I'm sure it's a big role. He's worked with Ryan Coogler twice before.

Michael is not the male lead in Black Panther but no way would Ryan Coogler want Michael in the film for a small part. Maybe Michael is the second male lead?

So basically a sidekick...shame...He could easily do much better.

Fact: 31.5% of IMDb users wanted Avatar to win Best Picture.
Fact: 31.5% of IMDb users are idiots.

It's not a small role, he's a major Black Panther villain (who is killed in the comics, twice...).

perhaps he may show up in a BP sequel or another Marvel film if he isn't killed off

U were wrong

Maybe Marvel is trying to make up for the disaster he was handed in Fantastic Four.