I don't think it's black and white; you can have an opinionated, simplified front end, and a back end that is wide open. The back-end makes some things easier,

I don't think it's black and white; you can have an opinionated, simplified front end, and a back end that is wide open. The back-end makes some things easier, such as testing, and helping admins deploy to 100+ users. A flexible back-end can even be used to create an opinionated front-end. Consider a "factory defaults" file; preset any behavior, whether or not it has a checkbox. Try every combination, and convince yourself that one is better. Even with these decisions made up front, the interface is there to let other people disagree with you. Mac OS X has a nice balance, because the built-in "defaults" command line program can tweak any setting that would also be available in the application's code. Just because a program is a GUI, doesn't mean that it should rely exclusively on GUI elements for configuration.