HTML forms, XForms, Web Forms - which and how much?

Personally, my reaction on first reading the XForms and WHATWG Web Forms
description was that it was irrelevant.  Irrelevant to me at least.  The
declarative approach in HTML is doomed to be incomplete (compared to
behaviors in script), and adds considerable complexity to HTML.  As I don't
expect to be using this (for a rather long time - if ever), as the entire
approach seems to be in the wrong direction - I've been pretty much ignoring
the discussion.

On the other hand, this does add bulk to browser implementations, and by
sheer bulk makes programming using HTML another notch harder to learn.  This
touches on a point of working philosophy.  Is the HTML spec going to be a
union of all proposed features, or a minimal subset?

Personally, I am hoping for something more minimal. :)

On the other (other) hand, I don't pretend to be channeling any sort of
universal truth, so perhaps I'm wrong and XForms/Web Forms is more
worthwhile than it appears.