For me, it's the over saturation of the product -- moving the draft to May, for instance.
Then there's Thursday Night Football. More often than not, it's a mediocre game with both teams coming on four days rest. Last night's Falcons/Buccaneers debacle epitomizes this.
Roger Goodell's greed has oversaturated the NFL. The first rule of show business, of which the NFL certainly qualifies, is to leave the audience wanting more. How can you do that when the NFL is on Monday night, Thursday night, Sunday afternoon, Sunday evening, and then Saturdays at season's end? Throw in the ridiculous London games, the draft being dragged out for days, the combine, and then the 24/7 NFL Police Blotter...
There's too much of a good thing. Throw in some of these ridiculous rule changes to significantly favor the offense and it all adds up to more and more fans getting turned off. It wasn't broken before, so I'm not sure why Goodell has felt the need to tinker with it so much.
