The Pats should have signed him to a 3 yr deal prior to this season. They could have given him some upfront money and paid him a total of $25m over the 3 yrs and even have him cuttable in year 3. They will probably end up moving on because he now will want a 3 yr deal, which is realistically too long at this point. But bottom line, the Pats are much worse off without Welker. Sure he had some big drops that cost them but his overall consistency is what got them to where they were.
Sure his productivity will drop at some point, but we haven't seen it yet. Pats fans are conditioned to see him leave - I'm not sure they appreciate him the way they should. Playing against him, I think Jet fans are not said to see him go, assuming he does.