This is one feature I would really really like to have. At least the ability for admins to use html, and have everyone else read it, while leaving the forum open to replies.
Currently in vb3.8 html can be used in a forum which admins can post html into, but the only way to keep others from posting html in it is to lock the forum. If I enable html in a forum, post html in a post, then disable html so others do not post html, all people see is the unparsed html. The only other way to use html is in notices.
I've never had to use HTML personally, but it could be a nice idea!
And another... come on Kier, you know this was one of the eternal requests for vB and it was always pushed off into 4.x (i.e. indefinitely, until the whole engine gets rewritten). I assume that since you started XF from scratch "can't be done" doesn't apply any more, right?