Until I see the final details, I'm going on the notion that the deal has an easy out. This signing reminds me of the year they brought in what felt like 400 TEs. We could see Britt sign, and have a WR contest of
Dobson
Edelman
Amendola
LaFell
Thompkins
Boyce
Britt
Harrison
Others
That's not any kind of murderer's row.
Definitely not "murderer's row", but it has the potential to be pretty darned good. Edelman is solid. Amendola has ability (health is the issue), Dobson has an awful lot of potential. And LaFell is a big-play kind of receiver that the Pats have lacked recently. 2011 and 2012: 17.0 and 15.3 yards per catch, respectively. That's really good.
Throw in Gronk plus another quality TE (hopefully drafted), and that's a very, very solid receiving corps. Let's be honest, what Brady had at the WR position during the super bowl winning seasons wasn't exactly murderer's row either:
2001: Troy Brown (excellent), David Patten, Terry Glenn (just 14 rec), Charles Johnson, Jermaine Wiggins (TE)…. one great player and a lot of meh
2003: Brown (declining), Deion Branch (solid), David Givens, Patten, Graham, Christian Fauria (TE)… Again, not exactly a star-studded cast
2004: Givens, Branch, Patten, Graham, Watson…
You get the idea. I don't see why this current group (assuming Gronk's health is fine and Amendola is better) wouldn't be easily as good as those groups, and probably a lot better.