(div class="red"
(p
(Hello, World!)
)
)I'm not sure what problem this solves. It eliminates the tiny bit of work that is typing the extra characters in a closing tag, and in doing so you lose all of the other information as to what exactly you're trying to close. The end of most HTML douments would be ))))))) (plus a mess of indenting).
I can see this causing many more problems than it would solve; I'm okay with typing three extra characters to avoid lack of confusion.
The current syntax may not be ideal, but I don't think removing the object type from a closing tab is a good way to make it better.