You claim that the defense made him better, and yet why couldn't Brodeur or Hedberg put up numbers anywhere close to what he was doing? Kinkaid's numbers were also significantly worse in the two good Cory years (combined).
Yes, Schneider was shot by the time the Devils went to the playoffs in 2018, he had gotten injured the year before and was never the same goalie. Between 2011 and 2016 he was a top five goaltender and never got the opportunity to prove it, and his reward for playing behind shit teams is to be slagged by guys like you who compare him to MacKenzie f-ing Blackwood and question his mental focus. His mental focus! Knowing that his shitty team is likely to score 2 or fewer goals for him and that he has to be the difference.