Guild Wars 2

With sieges placed from blueprints there is no problem. You just place a new blueprint and in case a siege gets heavily damaged but not completely destroyed you already can build another one as precaution if you think the first one will get destroyed completely soon.

But: At towers, keeps, SM you can repair walls and doors. Sieges can just be damaged by single moving players until they are almost dead… then later they can be cleared fast if the enemy zerg decides to arrive. And you can’t prepare and repair them to full health. You’d need to hope for an enemy to destroy them completely and then wait for the built site to reappear again.

It should be possible to repair these sieges – only the ones at towers, keeps, SM(oil, mortars, cannons). Should require supplies. An additional skill while you man the sieges should be used(cause you only have one F key that usually is used to repair but here used to man the siege).

To prevent counter-repairing while the enemy is attacking: Every time the siege gets attacked make a timer like 5 minutes(debuff)… always resetting to 5 minutes every time it takes damage. If it is safe for longer than 5 minutes you can repair.