Preview for comments
In 2009 there was a request for comment previewing, see Preview for comments. It was marked with status-declined. I'd like to see if this feature could be revisited.
Often when I use the linking mark up, I mix up the order of the () and  or make other types of markup mistakes. When posting a question or answer, I can quickly see the mistake I've made. When I do the same for a comment, I have to submit the comment, see how it looks, and quickly try to fix it before the five minute timer runs out.