When you are creating a new post/reply and hit the "preview" button it shows what the post will look like, but you have to hit "edit" to go back and then hit "create" to actually send your post. It would be really nice if we could create the post directly from the preview page (I am someone the obsessively previews even the simplest post to make sure it doesn't look like complete butt).

this is a good idea! do you think you'd prefer if keyboard focus went to the submit button so that it's an easy "return" keypress or keep the focus on the "edit" button?

Id prefer preview personally, since thats the "safer" option.