One of his His XG numbers has him around 48% this year... If we had a team full of guys like this we would be loosing more often than winning.
Bolded is not true. XG doesn't count the ability to score. I just guess Scheifele and Wheeler have even lower XG%, but that doesn't turn them bad players. Looking for shot charts by Laine also tells you that he can beat the goalies from a far without a screen so essentially he can turn many low-XG chances into high-XG chances, and he did that also back in FEL.
Just use WAR(82) if you need a decisive stat on someones contribution on winning. Laine had huge WAR numbers last season, and I guess his numbers are quite good this season as well. The only problem is these stats are hidden somewhere under a rock and you cannot pretty much find those unless some stats guy tweets them after a season.
Let's forget the fact that Laine has been great on PP, contributing to victories. If we take into account only the 5-on-5, Laine has +17 goal difference (I see that empty netters do not count). Buff has +12, Perreault +11. Stastny has +10, but most of that are from his previous team. I don't think you can ask more from a player.