I'm willing to give Son a season. Although my suspicion is it was nothing to do with his injury last season. Sure, an injury is going to limit your ability to run/sprint/stop
But it doesn't affect your touch, decision making and overall awareness. Those are all the things he struggled with all through the season.
I'll put a caveat on that though. Son wasn't the only one who went years looking like they couldn't control a football. I would say it was so bad, that our style of play was best described as "ping pong football" as the ball bounced off players relentlessly.
Maybe they weren't practicing in training enough? Or maybe our scouts just accumulated too many players with dismal first touches.