IS hasn't more impact on a driving layup than JR. The reason behind that is that it will be easier for a good outside shooter to score a driving layup than for a player who is only able to drive (for example).
I think i know what you are saying and I kind of agree with you somewhat.
What you are suggesting is - that if a player has lots of different skills, and lots of different abilities, this gives him a vast array of basketball weaponary to use and as such, he will be a better player at everything.
eg: Because he can shoot the 3point shot really well, his defender will defend him really close, which gives him a better chance of driving past him and scoring on driving layups. Or because he acn hit the 3pt shot but is playing at PF, he will hit more 3pt shots because the defender will have poor OD etc etc.
I think logically, this happens in real life. and i recently suggested this somewhere, and i think that, from a 'shot selection' perspective, the GE will try and pick this player more because he will have more mis-matches to expose. And i think we can discuss this later on, because the way that the GE 'selects' which player is going to shoot will be a very complicated thing.
But if we were to just talk purely about the isolated situation of, two players, performing layups, with the exact same defender, then surely IS makes a difference to % that one will make over the other?