For example, this system is pumpless, while the rest of the system evolved in the presence of a pump. In mammals the vascular system is continuously monitoring and optimizing blood-vessel diameter as a function of the waves of blood flowing through them. You don't get that if you have an artificial heart.
I bet movement also plays a role in fetal brain development too.
Therefore ideally the bag should be hung from a robot arm programmed to move like a sheep moves (maybe from recordings of an actual sheep), including sleeping at night etc. And the bag should gently pulse as though there's a heart and lungs. Also the miserable factory where these clones develop should play sounds of open pasture and birds, sheep bleating etc. That way they will be properly developed lambs ready to go to the abattoir. (edit: sorry for the sad ending)