I'd personally welcome the dist/www distinction. Reason's simple - I'm amongst those who simply don't have that much space available. On my secondary mirror (which has 6GB available) I'm already struggling when a new bunch of TorBrowser versions is released, no way I could keep it up if 8+ GB was the minimum
Also, the WWW-only version would open up a chance for many more mirrors on all kind of cheap/free hosting providers.
Just a heads up to folks here -- the dist/ part of the website will balloon to 8 or 9 gigs soon, once we put our Tor Browser updater infrastructure in place: https://trac.torproject.org/projects/tor/ticket/12954
I pondered whether it makes sense to let people volunteer mirrors of the html pages but not the dist/ files, but maybe that's just too much of a hassle, and besides most people probably want mirrors for their dist/ files.
Let us know if that was a horrible choice. :)
Thanks, --Roger