There are a few things Dak isn't able to do yet that he will do one day. Romo can do those things right now if he's healthy.
There isn't a wrong answer, which is the beauty of it.
yes, but there are also some things Dak can do that Romo cant. He is a threat with his legs which changes how defenses play and the run option is there which has opened up some things for the run and pass game as well.
Tony can read the defense presnap better but Dak is generally quicker to get rid of the ball and seems to be better right now at getting out of trouble than Romo would be sitting back there.
So you gain something with Romo but also loose some things without Dak. The fact that Dak has a very good passer rating and completion % tells me that what your going to gain with Romo may be only slightly better in the passing category that what Dak has now.
So to give up all the other things Dak can do for a slight increase in passing offense seems like you are giving up too much to gain a little.
Then add in the fact that the team is on a roll and the offense is playing great and in sync together right now.