The irony is you're posting on HN, which does exactly what you suggest no one will tolerate. How slow is this form submission for you? ;-)
On the other hand, I don't think it's usable for other crowds. I spend most of my day inside vim, so I'm used to switching windows and going back all the time but I don't think that having to load a submit form in a new page, losing all context of the conversation tree is particularly usable.