Clearly New England must think that Danny Amendola is a special player. As someone who has had him in Fantasy Football the past 2 seasons (have tracked him quite closely, permanently on IR, basically), and watched him in divisional games, I would say that he is really quite good. Wes Welker, he's not.
Necessary? It's a two year deal, brother, it's 6M dollars for a guy who is the QB's best buddy on the team, and averages over 100 catches a year. Even if he had
appreciably declined physically, which I haven't seen with my own eyes yet, nor can I see it on the stat sheet (which, as you mentioned isn't the point), that type of production is still ridiculous and the commitment is 2 years! If you want to diversify the offense, add some different types of pieces. I simply don't buy the idea that Welker made the Pats predictable (again, last year, the injuries to the TEs couldn't have helped), or that his presence was anything other than good for that offence.
As a stat observation, I find it interesting that he had virtually the identical number of targets last year as he had the previous season, when both of the TE's were healthy. Not sure what that means, especially with the run game on the way up

I would have expected more with their absences, although I suppose adding Lloyd would account for some of that. If the Pats really needed a structural shift, you'd think they would add a different type of player - not a like for like, which is what Welker effectively is. I mean, Gronkowski, Hernandez, those guys certainly aren't short on targets, either, how many times are you going to look for them? Amendola was a target machine for Bradford, he was Sam's security blanket. I see this as inserting as close a thing as there is to Welker into the offense, just for a little more money, and a longer term.
As for the ACL injury, well of course he would have missed the rest of the season, buddy

The point I was intending to put across was that he bounced back extremely well, he's dedicated to his body. He clearly takes very good care of himself.
Sorry bud, not trying to bring you down, or anything. Just think it's brutal for the fans.