Assuming your group has enough damage, you should only get hit by two repels. Black Mages and SMNs have Swiftcast which they can use to continue dealing damage while they return to position, and Paladins at least can prevent knockbacks. But if you're at the point where you need to squeeze out extra damage in the form of preventing repel, it suggests you have larger problems. Generally speaking, having a full rotation of Cleric Stanced' DoTs on Demon Wall will be more dps than one attack from the other three party members from a (possibly) prevented Repel.
