Your points are noted.
But if you watched Lane play NCAA, he was also a defensive liability in his defensive zone. There's a reason (and a valid one) why this offensively gifted defenceman fell to the bottom of the second round in his draft year. This kid will have to play sheltered minutes his entire career. But the minutes/situations that he will play (on the power play, 4 on 4, in overtime and in game situations where offence is needed) will more than make up for his defensive limitations.
As I have previously stated, hockey, like all professional sports, is entertainment. There is no more entertaining player currently on the Canadiens than Lane. You can feel it in the fans reaction when Lane has the puck. Their anticipation that something special is about to happen. When's the last time we had a player that caused a similar anticipation of excitement? Kovalev? Richer? With the now unfortunate injury to Laine, that anticipation factor has never been more pressing.
Hughes is a realist. He knows that his team is several years away from being a consistent contender. Until the arrival of the offensive depth at forward ( Demidov, Hage, etc.) that he has craftily assembled, the Canadiens will again have to rely on a strong top line, a mobile defence and competent goaltending to remain competitive. Lane adds a welcome dynamic flair to a re-building team that is not quite there. He offers excitement and hope for the future for the team's long suffering fans. There is no way that Lane is sent to Laval. The fans won't accept that. They'll embrace the excitement and hope that Lane offers regardless of his player's defensive warts.
Its all about entertainment.