The two dropped TD passes in the first game is your difference in points right there. Also, you have to consider the points Romo consistently gives the other team in pick 6s which cancels a lot of those points out.
Dak is intelligent, more calm under pressure, and makes better decisions with the ball than Romo does. I think the most important element is his ability to run though. When we start utilizing his running ability even more, it is going to be a nightmare for defenses to stop.
I don't blame the coaches for being ultra conservative in the playcalling so far. You also have to keep in mind that Dak's arrow is pointing up, while Romo's is pointing straight down.