It can depend what you add and why. Got an AML/ML academy player that was an excellent dribbler and scored from close range. I thought (stupidly in hindsight) I'd give him Shadow Striker to make him an all rounder with superior shooting ability too.
He does shoot more now and scores from shots, but he he shoots where before he'd have dribbled. Can't say for definite it was the SA but it feels like he scored more from dribbling than he does now from shooting.
So for a good performer I'd say SAs should be given (if at all) to enhance what they are good at.
But who knows - and that applies equally to those that say it doesn't work as those that say it does.
