Tony Hawk was just on Joe Rogan, it was pretty interesting to hear how he came up. It would be interesting to see a doc with all the pros from around that time in the 80s when skateboarding was blowing up, especially guys like Christian Hosoi (who was arguably "better" than Tony, but caught up in drugs). Then the change when vert skating died off and street skating became the thing, to where the sport is now with pros like Nyjah gearing up for the olympics and stuff.
There's a lot of stuff on the major sports already like the Class of '99 (soccer), so I think it would be cool to have a doc on something less people know about. I liked the Steve Prefontaine movie, so I'm thinking maybe something like high jump (covering the fosbury flop), pole vault, or maybe even speed skating (and eric heiden's massive quads)