Currently the site always shows the latest Screenshots/Comments on a respective page. Having a vote system for useful information and/or best screenshot/comment/whatever would be nice.
While having a comment shown on the main page of an item is nice, it would be more helpful to show the most useful/voted comment there. For Screenshots, a good shot could be replaced by a lower quality and be shown on the item, which isn't all that nice for people that put some work into their shots ;)
On a sidenote regarding that, deleted comments should not be shown there at all (i.e. http://xivdb.com/item/8588 - one of many - shows my comment from a year ago that I deleted after the vendor listings were implemented).