I guess it's his delivery. I like the knowledge and insight he brings, but he also comes off as douchey and childish when he tries to be so exuberant and funny.
During the last 2 minutes of the game, he said "this should end the game" or something to that effect about six times. He just seems a little unprofessional. Maybe I'm just feeling old and cranky.
I don't know. I was pleasantly surprised by Romo's commentating abilities this year. He's a little goofy at times in presentation but when he's talking x's and o's or just describing 'what' is happening on a particular play and breaking it down I really like what he has to say and it makes the game even more interesting to me. I was never a Romo fan either.