I look at two things with Parayko. One, he does play the hardest minutes: defensive zone starts, 5-on-5 against top lines, plus penalty killing. And the Blues had excellent penalty killing last season. Two, it's been a while since he had a good defensive partner. While Parayko's metrics were a mixed bag last season -- good defending zone entries, bad on zone exits, good on making offensive zone entries, not so good sustaining offensive zone control -- Nick Leddy's metrics were much worse.
For all of the fan yelping about Parayko, he was plus-32 in February, March and April. I know that plus-minus is not considered a comprehensive evaluation tool, it does prove the Blues fared well at even strength with him on the ice.
Was he great during the first half of last year? No. Was he great against the Avalanche in the playoffs. No. Was he a vital part of the team's strong second-half finish? Yes.