Thief is a great game, as is System Shock 2. Shock 2 has a great interface. Of all things, High Heat Baseball. The tune files are a great idea for users to edit their own gameplay. We've incorporated that kind of thing into our Construction Set.
Players can edit the game to adjust everything.
So if someone thinks the Athletics skill is too easy to increase, they can adjust the number. Even Redguard, which was an adventure game, was big and non-linear. Every TES game has to let you create the kind of character you want, and then do the things you want. We would never have a TES RPG force you to be a certain character or go down a certain path. Daggerfall's character system is awesome.