to be honest, I like the current shooting system.
It think it's quite realistic becuase all you need in Shooting a ball (in real life and in game) is --- FEELLING.
When you feel that the routine is good, then it will probably drops to the basket (say 90%).
I like that feeling in playing NBA Live.
A power bar is a good idea but I would say it's better to see it act like an indicator ONLY.
I think the current system is using the similar way to determine the shoots but hiding the power bar to the users
I played NBA Live and Winning11 (PES) everyday so that I know what you mean, beside, I can say that the shooting systems are actually quite similar.