Some fans are not happy with this new look, but as for myself, I personally give the change a round of applause. There are too many generic FPS games these days and with this one being a FPS and RPG at the same time, a little change in the graphics to mix it up a bit and differentiate the title is a good thing for Gearbox to do.
A new post on the Gearbox forums confirmed the stylistic transition from standard 3D to beautiful cel-shaded.
Though there’s always the chance some people could be turned off by the style, it was decided that, overall, it fits the game and creates a more visually interesting experience. Our concept art had this incredible, distinctive style and feel that fit so perfectly – the game has not become less detailed or washed out at all.
Rather, it retains the detail and style that’s often lost when we move from concept art to 3D. It stands out, and makes the gray-and-brown bleak landscapes, while still bleak and inhospitable, memorable and recognizable. The entire world has life to it, from the creatures to the very rocks and dirty walls.
Borderlands Goes Cel-Shaded; First Image of New Style [Deeko]