To play rotation pool at a high level, most shots will be hit with spin. If your system is to be complete, you will have to account for this. Unfortunately, no spin compensation system has ever been made that is even close to good enough to deserve the term "system". Some very admirable attempts have been made, but sadly the above is the case. All cues have different amount of deflection. All cloths are different. And even if you had a cue that was a "standard" and every game was played on exactly the same cloth, brand new there is still the problem of throw being different with speed. So a system like "backhand" english, which is often applied to various aiming systems, won't work because inside and outside english throw the ball opposite ways. Backhand english only works on very fast, close shots, where throw is not so much of a factor and curve isn't either. It only compensates for deflection, not curve and throw. You COULD have various bridge-lengths for speeds and distances and outside/inside, but then it quickly becomes so complicated that you completely overload your brain keeping track of it all.
Rote repetition will always be a part of pool excellence. Though many people try to sell miracle cure-alls, no such thing exists. Aiming systems are not worthless in teaching, however I have a very hard time imagining playing A-level pool with an aiming system used on every shot, without significant, experience based compensations for throw, swerve and deflection. When we're talking pro-level I think it's absolutely impossible. There are just too many variables to consider in throw, swerve and speed.