Meantime, Jerod Mayo is 26th on the list of Pro Football Focus' ILB/MLB rankings vs. the run, and he's the prime run-stopper on a team with below-average YPC against it despite the fact he's playing in probably the best situation for any run stuffer to excel in a 2-gap defense with Vince Wilfork in front of him. Not to mention the guy gave up more yards in coverage than any linebacker in the league besides the prestigious Paris Lenon.
The fact that you rely on PFF to tell you that Mayo isn't a good LB takes any credibility you hoped to have away from you. First, and foremost, PFF is a hack site. They have no access to the ALL-22 films and they are GUESSING as to who is supposed to be doing what. Not only that, they penalize a guy like Mayo who makes a tackle outside of his assignment. If Mayo's assignment is the A&B gaps on the left side of the O-line, but he breaks off and makes the tackle on the right side, he's penalized because the other ILBer didn't do his job. Yet, PFF doesn't take that into account. That being said, the Pats D-line was in shambles last year. They lost Ty Warren to start the season. Mike Wright missed 6 games games and a good portion of a 7th.. Myron Pryor was out for 6 games and part of an 7th. Gerard Warren had to play the last 4 games injured. Ron Brace was lost for the last 3 games of the season. They had to make do with the likes of Terdell Sands, Landon Cohen and Brandon Deaderick. As well as rookie Kyle Love. So, I would expect Mayo to be making a lot of plays "down field".
Also, it's clear that you don't really understand the 3-4 2 gap system. Wilfork does not line up right in front of Mayo. Wilfork lines up on the C, covering the A gaps. The RDE is in charge of the B & C gaps on the Right side. Mayo lines up on the guard, essentially, so he can cover the A & B gaps on his side of the field.
You also seem to be severely over-looking the fact that the Pats had an extremely young defense last year. And 5 brand new starters to start the year.
As for them having allowed 24 points or more 8 times last season and a 9th in the post season, this is true. They did. But despite everything, the Pats still finished leading the league in turnovers. They also ended the year averaging 19.6 points allowed. Good for the 8th best defense in the league. They also finished 14-3 (including the play-offs).
Like any fan, I think that this year's team looks better. The additions of Haynesworth, Carter, and Ellis to the D-line, with the return of Leigh Bodden at starting corner should help solidify this defense. My only concern is at safety opposite Chung.
What I see in Edds is that he's a young, smart guy whom I wanted the Pats to draft last year. He's was a very good cover guy prior to his injury. Advances in the field of ACLs has allowed people to return to what they do at 100% or better. Even with a meniscus injury. I can speak from personal experience on this. He's a guy that I think could end up replacing Guyton on the Pats. Why? Because what Edds lacks in speed he makes up for with instincts. For the time being, he'll be inactive or he'll only be on special teams if the Pats activate him. It will be interesting to see what happens..