I agree with you that Byfield needs to work on his shot and that he will never be a true goal scorer but let's be fair - every King this season has been guilty of missing wide open nets, shooting into the goalies crest and shooting wide. He will get better, but only the future knows by how much.
Our best goal scorers are only average 12% and 11% lifetime so Byfield isn't that far off. That said, he ranks in the upper middle currently within the NHL. Now there are factors which give players an unfair advantage, time on PP1, which Byfield has not received the luxury of. That, in itself, will bridge some of the gap.
Tuch has a 11.8 shooting percentage over his career which already ties that of our second best goal scorer. On top of that he has a 15.3% this year with zero PP goals. Though it is an up year for him, that is an elite percentage and stat. His season high is also a 16.5% during a season where he scored 36 goals. All this underlines that Tuch is a far better goal scorer than he is being given credit for, and a 30 goal season, if given top line playing time, is not a fluke.