what juice means, that we had to merge a lot of things into "main" skills else it would be to complicated to play the game.
So rebounding and inside defence also includes things like "muscle", driving includes speed of a player outside defence reactions, spacing, antipation ... if we made a skill for everything which could be important for a player, we would have 50 or more skills and to be honest did you understand the engine with 9 variables? Would it be easier with 50?