Well, there's a reason they are doing that to diablo. Ever wonder why D2 didn't get anymore expansions? Because it's such a mess that they got very very lucky it holds together. They learned how to control character power during the development of WoW and that allows them to control the growth of the game, thus facilitating expansion-based business model.
In other words, they want to sell us a D3 expansion every year and the only way they can do that is by controlling exactly the limits of character power.








