Who's to say that Wilfork can't be replaced? Belichick drafted two NTs last year for a reason, and while neither seemed ready to step into Vince's shoes full-time, I wouldn't be at all surprised if, after the a franchised year from Vince, one of them is.
For all the complaining on this board about how Vince deserves to get paid in accordance with his demands (without knowing what those demands are: seriously, how is this any different than the behavior that Seymour was demonized for?), where exactly is this coming from?
Wilfork's very, very good, don't get me wrong, but if he wants near-Haynesworth money on a long-term contract, while continuing to show up to TC every year heavier than he was the year before, then he's not going to get the deal that he wants. In which case, the Pats will franchise him. You sentimental types need to just accept that, because it's how the Pats will always do business under Belichick: they're not going to throw stupid money at players, and that's a good thing. People have been crying foul about how it means that FAs will never come here since the day Belichick got here (and before- that complaint was present in his Browns day, as well), and it's never been true.