One would think that Arena is for competitive players such as myself, so we can have a less tedious way of competing with cutlass and cannon. Trouble is, the way to win in the Arena, much like in Adventure, is to avoid fights at every turn. The winning crews are those best at fleeing, not fighting. Arena's not competitive PvP, it's competitive P&E! Of course, PvE players won't play it because it involves battle and risk. So who is it for? It's not for pirates, as fighting leads to loss, and it's not for delivery mariners, because it has some fighting and loss. That's not to mention Rare's recent announcement that one can level up Sea Dogs all the way without ever stepping foot in the Arena.
To awnser the question, I have to say that Arena is for no one.