Worse, Riddick was a vanity project showing off how awesome he is.Vin Diesel does have chemistry and can act great, but he's gotten lazy and complacent over the years. The first F&F movie and the Riddick movies prove that. In the third live action Riddick movie, he's alone for the first hour. With nobody, but a CG creature to interact with. He does a great job during that park, but the second half is just Pitch Black all over again, but less interesting.
Also, IIRC, he had a contract saying his character couldn't lose fights in F&F movies, and The Rock did as well.