WoW has a reputation for user interface customizability, not a high reputation for it's actual user interface. And plenty of people play WoW with out user interface addons. And even among Blizzard's titles, what other games allow you access to UI APIs for standard customization? Why is D3 lacking a way to allow the same interface customization that WoW does? Hmmm?
What people want in a UI are three things...
- Effecient to use and work with
- Easy to learn (intuitive)
- More Satisfying to use
If an interface does well with all three of these, you quickly find that people don't bother to personalize it because they see no need. But when one or two of these are lacking, well that's when you start seeing people demand "I wanna customize my interface with all this stuff that sounds real cool if I don't think about it."