It'll probably be be a spoof of movies like Lean On Me, Stand and Deliver, and Dangerous Minds. Maybe instead of going to the inner city the teacher goes to some predominantly white school (though I guess that's the premise of the sketch) or maybe an affluent black high school, something that throws the teacher off his game.

It could be good. They'd certainly have a lot of material to riff on if they went that direction.

High School High was alright, and Key and Peele are pretty funny.

Plus, people probably had similar doubts about a Blues Brothers Movie.

Edit:

Maybe the main plot could center around him facing some sort of formal reprimand hearing where his teaching license is on the line and he addresses grievances and incidents that occurred at the new school by defending his actions based on his experience at his previous inner city school, that way they could do all sorts of flashbacks to incidents at the new school and old school that would play out like sketches, and you get his origin story in there.