It's no secret that there was a bit of a shake-up at Blizzard North back in 2003 when Bill Roper, Max Schaefer, Erich Schaefer, David Brevik, Mark Kern, and quite a few others left the company to form new development companies like Flagship Studios, Red 5 Studios, and Hyboreal Games. Interestingly enough, former 3D artist Alan Ackerman has posted a couple of creature models to his personal blog that he created for "an unreleased game for Blizzard North in 2003" that look very much like they could have been for a Diablo title of some kind. Siliconera thinks that they may have been for a previous iteration of Diablo III or even a Diablo MMORPG based on Alan's short description for the Flayed Hound:
We using pretty simple texture maps; at the time, massively multi-player engines limited the technology that could be used on models. It also did not make much sense to use normal maps and such objects that were going to be pretty small in game (at the time there was no planned zoom or camera controls).