GW2 underwater combat?
Probaly not, but i'm more thinking of assasin's creed style underwater exploring.
Can't wait for dives into the corals and exploring the underwater world, and buying guild ships and sinking all those other fools who think they can rules over the seven seas!

Linky:
http://steparu.com/previews/mmorpg/2008-black-desert-upcoming-future-content​