I don't know if I buy this "tenured vet" thing with Johnston. He scratched a number of those in the playoffs to dress Scott Wilson, who had, what, 3 minutes of NHL experience and was in his first pro season? He leaned heavily at times on Taylor Chorney, who was an absolute nobody.
Kunitz was where Kunitz was because the only wings that were reliably above his level (low as it was), were Hornqvist and Dupuis, the latter of whom missed the final 70 games of the season. Maybe Comeau, but after his hand injury, him and Kunitz were probably a wash. BC tried harder, CK made smarter reads. Downie was scoring more, but he was getting 2 freaking minors every 10 minutes of ice time. Whether he earned them or not, you still have to kill the penalty.
Need 4 better guys for Kunitz to not be on one of the first two lines. By the middle of February we had 1. Arguably 2. But MJ still had comparative newcomers like Winnik and Spaling playing above 14 for large periods of time. That's an obvious indication of displeasure in Kunitz's play, when you start throwing journeyman curtain jerkers on your first line over a guy who was on the top line of the eventual champion in Sochi just 13 months prior.
Regarding Perron: "why was Kunitz playing above him" isn't a question that anybody paying attention at the time should need to ask. A better question would be "why wasn't Perron scratched?" His play absolutely merited it. Tenure is no sort of explanation for why Winnik and Spaling would be higher in the lineup than Perron. Only Perron's garbage skating and wildly uneven effort level was. Spaling was less veteran and Winnik was a clock-punching merc with less tenure.
Answer to that is an extension of the answer about Kunitz--bad as he was, we didn't have 8 available wings that were likely to play less terrible hockey than Perron in the organization.