I hope the artstyle is more realistic and dark. From what we've seen right now the game is rather similar looking to Diablo 3 and Torchlight 2 and the million other loot RPG's. I would prefer it if Original Sin had a more unique artstyle.
Look at Baldur's Gate and Divine Divinity. They're not just memorable due to the great gameplay, story and role playing. They are also memorable due to their artstyles. I'm playing through Baldur's Gate again right now and asides from spells and water looking rather old everything else looks rather decent and the game is easy on my eyes. I'd even go as far to say that Baldur's Gate 1 has better graphics than Divinity 2, Oblivion and Fallout 3 but then again, all of those three titles used that HORRIBLE Gamebyro engine which sucks concerning texture.