Gearbox states on its community boards that the change was made to make a more "visually interesting experience." Allegedly, the gameplay hasn't been affected by the new art style -- not that we'd know, considering we've never actually touched the game, which is supposed to come out later this year.
[Via Big Download]
Update: Gearbox Studio head Randy Pitchford has sent out a statement (posted after the break) that the game's art style is not "cel-shaded." We've also learned that web-ready images will hopefully be available for consumption by the internet on Monday, and the game should be on display -- possibly playable -- at E3.
The PC Gamer cover [above; in full after break] features "an in-game screenshot with no post process," giving us an idea of the new art style and rendering tech.