For one thing, all those beautiful vistas in the trailer are part of a seamless world. For another, the combat is action-focused and features the ability to dodge and block. There's also something called horse-drifting, which the devs say is part of a battle and movement system inspired by Red Dead Redemption.
The game is class-based; current archetypes include Fighters, Sorcerers, Beasts, and Tamers, though the names will likely change going forward. Black Desert also looks to feature optional PvP as well as bind-on-equip items that don't drop if you're killed by another player. When can you get your hands on all these fine features? Not for a while, it seems. The devs say they're shooting for a Korean beta sometime in 2013.