The Frames feature does a lot more than fancy layout.
Unlike <TABLE> cells, <FRAMES> are independant of one
another and can be used to build compound hyperdocuments.
It also does more than an <EMBED> tag would; this isn't mentioned
in the proposal, but there's one more extension
(buried in the 2.0a2 release notes,
<URL:http://home.mcom.com/eng/mozilla/2.0/relnotes/>):
a new 'TARGET' attribute on the <A>nchor element which names
the destination frame or window where the head anchor should
be displayed. This will make it possible to create all sorts of
complex hypertext interfaces that aren't currently possible.
I haven't tried out Netscape 2.0 yet, but I think they've got
something realy good here. This proposal deserves serious
consideration...
BTW, the release notes cited above have a much better description
of the feature than the proposal posted here and in html-wg.
--Joe English