Do you think Node will be lean and mean forever. It's been around for about two years. Let it grow and it will soon become just as "fat" as Rails and Java frameworks. Funny thing about people reinventing the wheel thinking their approach is just so much smarter. In the end you end up having to face the very same problems Rails guys and Java guys faced in the past. Abstractions, reusable components for X, Y and Z and you end up with something like J2EE or Rails.