Sorting by date is done already...along with by name and author. Downloads will never be added because it proves to be a pissing contest of how many downloads you have vs. everyone else. I have never heard of sorting by comments and I don't really see the point. You could have 50 comments on a theme and have them all be negotive. We are working on other ways of doing some things...but right now its pending the rewrite of the site.