Basically I agree with everything SF said, except that I'm not sure about this: "...basic reading/posting/formatting cannot be any simpler." If you're concerned that the posting format may "scare off many new posters"(jj1000), then you probably want to hear from potential new posters, rather than those who have demonstrated their facility with the current site.
Also, to those who get (understandably) annoyed at the shenanigans needed for multiple quotes, I say, Use your words! Not your quote button. (see above)