He's not terrible. That team was much better than the announcer performance in the first game as you can tell that Romo has given up on preparation and Nantz doesn't appear to be paying attention to anything other than reading promos.
I think you can learn and understand more with the volume off... They all have agendas and do whatever producers tell them. Sure, I will listen to a qb that understands the game here and there but thats it... I understand football more than Shannon Sharpe. He played in the NFL. I did not yet his knowledge is not close to mine