perhaps they just didnt want another ultra realistic game
My assumption is that it was cheaper to create a stylized game as you can make liberal use of tthus lending to lesser polys/textures needed to get the job done, as well as having lower system requirements because of that.
I'm just hoping they rip-off TF2's context sensitive emotes and facials, because after having played over 50 hours of TF2, all the other online FPS games I used to play just feel lifeless in comparison.