Is it fair to ding Rails for that, though? Regardless of what framework you're working with, eventually you're going to be peeking under the hood. Of either the framework, the language, or both. Whether that's front-loaded or not, it's still there. So the question becomes which framework eases you into the deep end of the pool, rather than which is the least complex.

I've seen plenty of Rails apps that could have written better initially. But I haven't really seen any where it was impossible to refactor and improve them as a developer learns more.