1.) I'm assuming that Welker was struggling due to the blow to the head. That's the only thing that makes sense to me. The play where he stopped on a pattern led to an interception on a throw to Moss. That's not typical Welker behavior, and that changes the game.
Could it be that the jets plan was to neutralize welker at all costs, even with illegal hits. I think there was a game with Pittsburgh two years ago, I think, where welker was neutralized, and the steelers turned a close game into a rout. I think the NFL should look into this seriously. Go Pats.