I don't know if Sanheim deserved to be scratched, I do know him being scratched had little impact, positive or negative, Gudas would have screwed up in game six either way.
Sanheim did nothing special in the playoffs, he was basically "Meh" by any standard.
Hagg had a xGFrel of +37.78 for his SSS, which is probably as good as a defensive defenseman can possibly play.
Then again, few players had a good playoff series, basically Couts, Provorov and Laughton. Giroux and Ghost had a weird series, good Corsi for Giroux, good xGF for Ghost, awful GF/GA for both players. Voracek and Simmonds were decent but not top six quality, Raffl, TK and Patrick were meh, Filppula, Read, Lehtera, MacDonald, Manning and Gudas were awful ES, solid on the PK. Lindblom was just awful period.
It was pretty much a group effort. And we'll just ignore the awful goal tending shall we?
Focusing on Sanheim sitting for a couple games is ignoring the stampeding herd of Bison for the elk bounding by.
The problem was both lack of depth and too many top veterans failing to step it up when it counted.