Although your suggestion is probably not realistic given ICANN's devotion to trademark
interests, it would achieve the intended result of eliminating scarcity and much
of the motivation and rationale behind domain hording and speculation. This
is why I was the first and foremost proponent of SimplifiedDomains http://www.simplifieddomains.com.
Theoretically, it is the BEST solution possible. Categorization of the Internet is
not really viable (as I like to re-iterate ad nauseum). However, opening up
the TLD universe would have many real and positive effects. This is what SimplifiedDomains
is all about.
But, alas, Simplified Domains is just too bold of a solution,
and they were never politically involved.
-Jestiny