Should the Meg and Kracken be in arena? I say no because randomness ruins the balance of a fair fight and people can easily feel cheated. If I am having a ship battle with you and all of the sudden meg targets me I am now going to feel like I was not able to give the fight I could have and maybe it will cost me the game. Or maybe I have to spend and extra 5 minutes fighting a kracken that nobody else had to deal with. The way these creatures work now is fine in adventure, but random encounters can not work in a competitive mode.
However I would like to make a suggestion. I have wanted a giant crab in the game for a long time. If Arena is the team to grab the most treasure or acquire the most gold this could work very well. So let's say we put a giant crab in a cave somewhere in the middle of the ocean or on an island. And let's say this crab guards treasure. Now we have a PVE/PVP element in the game. (not including snakes and sharks) This would be like Halo Warzone, you could fight the crab and maybe nobody will interfere. You could fight a team and the crab at the same time. Or maybe you wait for another team to kill the crab and you swoop in for the treasure. I think there is a lot of potential here that will work in arena much better then in adventure. Heck you could even choose to just have treasure on the crab's back like in Moana and have people try and grab it without getting killed but in this case the crab is not killable. Well I hope you all like my idea. what do you think? do you want meg and kracken in arena? how do you like my crab idea?
EDIT: the crab would be 100% optional as a way to get gold without following the maps. Also though I think a position in the world so if people see a ship sitting in a particular spot people know they are doing the crab.