What I found bothersome in this is people ignore the smart game planning and good execution while making excuses. For example, in the 2013 playoffs, the Patriots blew out the Colts. They didn't do anything tricky. They knew the Colts had a weak run defense, so they put a 320 lb lineman in the game as a TE, used a 255 lb fullback and a 250 lb tailback. And they ran right over the Colts line and dominated the game. You would think other teams would learn from this and do the same thing against the Colts in 2014, but no, each team stuck with their regular game plan. In mid 2014, the Pats did the same thing against the Colts and again other teams did not copy the strategy and the Colts reached the AFC Championship. Again, the Pats used a 320 lb OL as TE, a 255 lb fullback, and a 250 lb runningback and ran over the Colts. That's just good coaching and old fashioned physical football. Yet, afterwards people accuse them of cheating. It's sour grapes from around the league.
The eligible lineman used against the Ravens was used by Alabama earlier in the year. Any team could have copied it, but Belichick is the only one to think of it and people complain. Go back a few years ago when they were using their quick no huddle offense. Belichick got that idea from seeing the success Chip Kelly had and brought him in to their training camp and explain how he does it. Other teams could have done this, but no one did. And then they complained that it was unfair and they were bending the rules despite the fact it was totally legit. I could go on...