Given that the coming release of emacs 25 ships with the eww browser, I think it would be worthwhile to make org-eww.el a core org-mode module. I have been using eww instead of emacs-w3m for some time now with no problems. Since org ships with support for emacs-w3m, an external package, it seems to makes sense also to support eww, the built-in browser.
I noticed that Marco Wahl, the author of org-eww.el, is on the contributors list, so, if I understand correctly, there shouldn't be copyright issues. Matt