Confidence is crazy important when it comes to the position of goaler. Markstrom looks like somebody that has been defeated and has been that way since Oilers destroyed him. Vladar on the other hand was playing out of his mind and in a big part of that was because of how confidently he was playing. Thinking you "can" stop a shot, means that you "will" stop a shot. Sutter rarely played Vladar for long-term stretches. I think there was a week around Feb-ish if I remember where Vladar got like 3-4 games in a row and then he went back to the rotational aspect of Markstrom gets 2 and then Daniel gets 1.
People are relying too much on goaltending on HFB with Calgary though, if you can't win games with more than a single goal then you're asking yourself for bad things to happen, which takes place in hockey. Things like a bad bounce off a ref, a weak defensive play, a forced play with the puck that leads to a turnover, a bad error in the offensive zone, etc. Goalers are there to stop mistakes, absolutely, but not all of their issues is because of Markstrom/Vladar IMO.