Paul's cues had a specific hit and the nylon insert was a part of that. I believe it had better contact than that of its brass counterpart. Although, I do agree that it could be a little more user friendly.
Once again you are absolutely correct. A cue is made up of numerous components and the cues hit is established from the cumulation of these components. Any change in the equation will give a different result.
I've always wondered who it was that came up with the idea for this insert in the first place. I have read that Paul was a woodworker and never played pool but Bob Meucci talked him into building cues and helped him set up and open his shop and that Meucci started using Paul's shop to start building his cues before he had a shop. Mr. Meucci never Used these type of inserts that I've ever been aware of so I wonder who it was that first put the idea into his head.
Dick