In my opinion endless repairs are fine as long dmg, dmg adsorption (thickness, hp, penetration) and repair amount match each other. Aka mirror match. Problems start to occur when one gets favored to much.
Fighting at range. -> thickness increase resulting in less dmg favoring repairs.
Fighting ships outside your ship rate -> dmg absorption + repair amount overweight dmg
Sometimes woods+mods+ books create a mismatch against stock ships.
When someone needs 15mins to demast should the game throw him a bone a la you did well now pick up your reward? Or should the game push him to maybe improve his stills and do it in 5mins to enjoy his accomplishment for 10mins?
As I said I'm totally fine with the repair system. It promotes action. While limited repair just favours the most cowardly player.