However, `package.el` defines an alist of `package-archives` which you can add entries to. My hope is that then someone will end up creating a less restrictive package archive to complement the offerings in the GNU one.
Nathan Weizenbaum, of Haml fame, has done some work on a project for creating Emacs Lisp package archives and an accompanying front-end here: http://code.google.com/p/marmalade/
I never had the feeling that I need a package manager to handle my external packages. Thinking about that now I guess it's because the packages I use share little to no interdependencies. I'd say that it's the latter where a package system has a really strong point.
But anyway, I'm looking forward to the new feature. I could image it'll be fun to browse a package directory and just randomly try new extensions out, just to see if I like them and be able to get rid of them as easily as I've installed them.
Cool.