Those water-girls. Befriendable, Amphibious(can walk on land and swim in water).
Every pirate game has them shouldn't SW have them too? They don't have to be half fish, half human. Just something close to that. More mobs that can swim and some special swimming befriendable mob would be good.
In vanilla there were pigs, caves have bunny man, I think mermaids would be a great mob to befriend. (Don't you even dare to mention those apes, not even a word!!! And apes can't swim so we cant drag them with us.)
This would only create a toxic environment. I get that this seems like a good idea, but it could quite honestly go downhill fast. Certainly griefers would appear less in the community, but other players would also get banned in the process. Say a Willow lights a log or a stump on fire for sanity, and it catches a sapling, which catches a flower, etc. etc. until it eventually hits the base. Purely accidental, but if someone reported that as griefing that player would be banned from a large amount of serves for just a simple mistake. Besides, not many players grief every time they play, and others have different definitions of griefing. Someone new to PVP may complain of someone destroying or burning their base, but that's just the name of the game d: