Xfce is not "GNOME with pieces removed." It's a completely separate code base from GNOME. You can check out the code at http://git.xfce.org/. Xfce does depend on GTK+, but that's just a graphics toolkit.
If anything, GNOME and Xfce are farther apart than they've ever been. Just compare a default install of GNOME and a default install of Xfce, and tell me how many similarities you see. Not many.
I view Xfce as the working man's desktop because it enables you to get stuff done with a minimum of yak-shaving. Rather than focusing on "the semantic desktop" (like KDE4) or chasing dreams of Linux tablets (like GNOME3), Xfce focused on delivering a usable desktop with no drama. And it has succeeded. It may not be as exciting as a catastrophic rewrite-from-scratch or as trendy as HTML5, but it's actually usable. I hope more distros consider using it as the default desktop.
Another thing Xfce gets right is not re-inventing wheels. GNOME has its own office suite (GnomeOffice), its own IDE (Anjuta), its own CD ripper (Sound Juicer), and on and on. Xfce takes the approach that if a perfectly usable program already exists for a task, it doesn't need to be re-invented.
P.S. I've done the "old-school WM" thing before too. I used xfvwm for a few years, and even used twm. None of those environments was as productive as Xfce because there was inevitably a yak to be shaved-- a configuration file that had to be edited by hand, or a bash script that had to be tweaked. Xfce is a great project and it's really worth a look, if you haven't tried it.