D's are 'worried about it'. They just can't stop it without leaving themselves open to damage from Moss. Big difference IMO.
Welker allows the Pats to dominate TOP most games, not allowing defenses to get off the field.
For such an average wr, he helps the Pats tally up a lot of W's, moreso than if they had a 'real' #2 wr. I agree he isn't what I or many would call a great wr, but he's the best in the game at what he does.
NE has never won a SB w/ him when Brady won 3 w/o lesser players. In postseason 2 years ago they took Moss away and it made that offense look human which allowed for the upset.