This is a strange argument, Josh Barnett is a person, not a style, and everything seems to be about him. Apart from Barnett one of the most recognizable Catch fighters in MMA would probably Sakuraba who spent most of his career as the smaller guy. Megumi Fuji is one of Barnetts top students and she is tiny. Ask got known for his double wrist lock (aka Kimura) and Fuji for her toe hold. Neither of those rely on weight, but are staple techniques of catch. Catch is just a different philosophy. It emphasizes top control and finishing a fight as quickly as possible in contrast to the "survival first" mentality of the Gracie brothers. Guard wasn't really their historically as going on your back meant losing. Any style should be adaptable to the person doing it, and any person should be able to apply their own strengths to the style they do. If you are strong use your strength, if you are big use your size, if you are fast use your speed, if you are flexible use that, etc. Barnett's Chest compression finish might not be a lot easier for heavier guys, but even small guys can use it to ride and tire out the bottom guy faster, even if it doesn't always get a tap.