How about incorporating pillaging houses into a new repair system. I gues it would be fun if attacking a island could leave some mark.
How about, all houses loose 2% daily. Each repair (same amount fo materials) fixes 5%. You can attack the house and depending on the type of attack it does damage to the house (ie a sword might take five hits to do 1% damage, while a cannonball mught do 3% on it's own). You can't do damage to a hosue under 10%. That means that it will cause a great inconvenience to them but you can't actually destroy their house.
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