RealGM

This is a stat that isn't really invented since it simply involves using basketball references bad pass column over the play by play turnovers column and dividing the players assist numbers by it. How valid does this sound as a stat, I feel like it makes some sense really quick here are the top 15 assist men since 01 ( that's the earliest year bad passes as turnovers count ) and here's there ratios
minimum 3000 pts scored and 200 games

AST/Bad pass

Chris Paul: 7.83
Steve Nash: 4.10
Deron Williams: 4.33
Jason Kidd: 3.77
Rajon rondo: 2.59
John wall: 4.26
Baron Davis: 3.82
Stephon Marbury: 3.75
Andre Miller: 4.40
Calderon: 5.28
James: 4.02
Westbrook :4.48
Rose: 4.47
Curry:3.40
Felton: 3.46

Thoughts?

To get all technical on you, we know if it's a 'good' (i.e. stat that helps gauging a players' offensive impact) once someone throws it into a 'Statistical Plus Minus' algorithm (like this http://godismyjudgeok.com/DStats/aspm-and-vorp/, called '(A)SPM') and the AST/BAD_PASS stat turns out to be a significant predictor/coefficient within the SPM framework

The ranking you posted seems very reasonable, the big question is if it adds anything to the already existing stats, like AST/TO

I think this is a better stat than assist/TO if you're specifically looking at passing prowess. I don't it's fair to compare assist/TO ratios between a PG who mainly just distributes the ball and one who attacks the basket a lot, since the latter might get many of his turnovers from getting stripped, offensive fouls, etc.