I remember Redbelt (2008) as being controversial when it came out - was it brilliant, was it pretentious, was it crap? We thought it was great.
Chiwetel Ejiofor stars as a Brazilian Jiu Jitsu instructor. His studio is humble, although he has some pretty good students, including cop Randy Couture. A woman with problems shows up, and causes more problems. Ejiofor breaks up a bar fight later on and winds up saving an action movie star (Tim Allen?!?). So on the one hand, he is broke and in legal hot water. On the other, he has made friends with someone rich and powerful in Hollywood. And he is being tempted to compete in a mixed martial arts tourney by promoter Ricky Jay. Oh yeah, Joe Mantegna is around, stirring up trouble.
If those last two cast members didn't clue you, David Mamet wrote and directed this. It turns out that he is a BJJ student and this was somewhat a labor of love. It is also full of Mamet dialog, but not so stilted and structured as to be over the top. The plot doesn't always seem to make sense - What is it with the treacherous Tim Allen, his wife and evil agent Joe Mantegna? But it all builds on testing Ejiofor and his statement that "There is no situation you could not escape from." The final fight scene is both inevitable and surprising.
There is a bit of fighting, but this isn't much of an action movie - more of an exploration of the martial arts.
Since it's a Mamet film, it's full of terse, tough, philosophical dialog. I don't think he ever goes over the top with it, although your mileage may vary. He has been studying Jiu Jitsu for a while, it seems, and the material seems pretty simpatico.