Sure it is. Case in point: iOS vs. Android. Windows vs. Mac. MythTV vs. Windows Media Center. PS3 vs. Xbox vs. Wii.

I personally like the heiarchial minimalist approach. You don't. It's subjective based on preference.

Again, preference. I might like having something completely different than you describe, like, say, a graphical representation of my player-character that I can drag and drop items onto, or maybe a CLI where I just type out what I want to equip. Does that make one bad over the other? Not really. It just makes them different. Bethesda has had this interface since Morrowind, and, well, I guess I've just grown accustomed to it.

Why? I mean why make it different across platforms when it functionally serves it's purpose? We're not talking about forcing a gamepad here. the mouse and scrollwheel works. that said, I actually use WASD + E (R, Y/N) without even thinking about it. *shrug*

Again, no matter what they release, an element of the gaming population is going to think that it's utter crap, so, why waste more time on it when you know what you have works, provides little/zero risk of a platform-specific problem, and, for the most part, looks exactly like the UI of the last several RPGs you've put out?