There's plenty of precedent. The plan9 guys were very explicit about not having variable colours in acme. The suckless.org team say that you can configure whatever you like, but only through changing the source code. BeOS aimed to have no configuration and good defaults.

I'd rather have something that was well thought through and is internally consistant than a grab-bag of customisation, none of which coexists well - like most linux desktops.