What it this "low task-switching barrier" ? I mean, even though, the language is the same, back end coding and front end coding are really different. For example, your front end development may have lagged because of lack of front end development knowledge, not because of this mythical task switching barrier that everyone is talking about !
Maybe not true for everyone, but I find when working on quick prototypes of web ideas, where I have to write both front and back-end code, the fact that they're both in the same language with node.js is actually a huge advantage -- much greater than I expected.
IMHO the main problem is that usually front end development implies XHTML/CSS integration and/or UI and/or UX, and that's a very different job from back end development.
