The argument is that the console versions has already had an effect on the design of the game some time during development. The decision to make versions for consoles meant that several aspects of the game had to be redesigned so that it can accommodate console gamers and as such, it resulted in the game being "dumbed down".
This particular argument is certainly making its rounds. And, in most cases, it's being used to validate the viewpoints of people who disagree with how Diablo III was designed. While having those disagreements is fine, blaming console for why they even exist is a pretty poor scapegoat.
No, the PC version of Diablo III was not designed for console from the beginning. It was developed for the PC with one major goal in mind: provide players with an awesome hack-and-slash computer game that's both fun and engaging. Whether or not we achieved that goal is certainly up for debate within this community, but it doesn't make it any less real or valid. All the decisions we made when developing Diablo III -- including combat, skills, character controls, user interface, and itemization -- were ones we believed would deliver a great experience on the PC, and the same can be said for the improvements we've made since launch. These decisions were not hindered (i.e. "dumbed down") by the development of a PlayStation version or altered to accommodate it.
For clarity, the PS3 version of Diablo III is based on the PC version and will include many of the same features as the PC game, including content all the way up to patch 1.0.7. From there, it's being tailored specifically for the PlayStation platform and will feature changes like a redesigned control scheme, camera perspective, and UI.
So, while there may be some players who don't like how Diablo III was designed for PC, the PlayStation version of the game was ultimately predicated by the PC experience (not vice-versa). If you don't like the skill system, the inclusion of the auction house, or how itemization works, that's fine and we certainly respect those opinions, but please try to attribute those disagreements to the right place. :)