I'm not sure I completely agree with this. Vince was without doubt a great 3-4 NT, and will never be considered a pass rushing 4-3 DT. OTOH I think you can make a serious argument that he upped his game and had his 2 finest seasons in 2011-2012 when he was used as both a NT and DT in a hybrid defense and became more than just a space eater clogging the middle. I don't think he ever got recognition for how great he was in those 2 seasons, and how much the defense was built around him - something that was nicely spelled out in an oft-cited Grantland article written just before the 2012 SB game:
http://grantland.com/features/bill-belichick-vince-wilfork-new-england-patriots-defense/
Since that article was written, the Pats have amassed a wealth of talent and playmakers around Wilfork: Chandler Jones, Jamie Collins, Dont'a Hightower, Devin McCourty (on the 2011 team, but since moved to safety) and now Darelle Revis, Brandon Browner and Dominique Easley. If Wilfork can get back to anything resembling his 2011-2012 form, the defense should be something to behold.