I've came across the idea in so many topics on forums. It could be great additional property yet hasn't implemented yet.
Wondering just because of it is concluded that it would be game breaking?
@Schulz I don't think it would be game-breaking or even that hard to implement (subs in some games can retreat).
However, I am not sure that it would improve the games. Limiting combat rounds has much the same effect as the former defender can move out at that point.
I concur. I think its a cool mechanic and I would certainly appreciate more optional mechanics but I dont think it would matter much. For balance it would have to be available after the first round of combat. But it might not matter because the 2 main strategies are to sacrifice a low value unit to delay the enemy's army or pile everyone into one spot to protect a valuable point/take on enemy's large army; at either point, defending retreat is probably moot.
But then again, having a defender retreat option might open the doors to more strategies.
Like others said, I think that a limit to combat rounds is a pretty good way to get this effect. It seems to me that most of the time it will either be in the attackers interest to retreat, or the defenders, and somewhat rare that both players agree to keep fighting.
I don't think it would be game-breaking, it would probably be a nice feature to have. But I'd be aware that adding decisions for a defender to make during an attackers turn can significantly increase the time it takes to play, especially for play by email.