Allen actually ranked toward the bottom of the league in punts that were fair caught. He did lead all punters in touchbacks however.
Maybe I'm just missing your point, because I'm not really sure how this points to what you seem to be arguing. Let me try again.
The Patriots have had a top-10 punting DVOA every year since 2009:
2013: 5th
2012: 10th (and I'd wager that Belichick blamed the punter, since he replaced him the following year)
2011: 2nd
2010: 8th
2009: 6th
In this time, the Patriots have never had a punter that I would consider significantly better than average. Hanson sucked, Mesko was okay for a while then he sucked, and Allen is generally adequate.
So why do the Pats consistently rank so well in punt coverage? Because their punt coverage team is really, really good. Starting with Slater, who is by far the biggest piece of that puzzle.
What you seem to be saying is that it isn't worth keeping ST specialists around because opposing punt returns aren't having a major impact on the game. The clear response to that, IMO, is that opposing punt returns aren't having a major affect on the game
because these guys are doing their jobs so well. It's flawed reasoning for all the same reasons why you'd never say a CB or safety sucks because he never gets thrown at. Actually, some people here do argue that, but at least we generally understand that their opinions aren't worth considering.
This whole premise just sounds like circular logic to me: a strict evaluation of context-less numbers without sufficient consideration for what those numbers mean and why they are what they are. Either that or I've totally misread your point and I'm arguing against a straw man, which is definitely possible.