• A preview option in the Private Message and Comment areas.

• A once a month PM, listing all of the birthdays of your friends, for that month- so you'd actually have some time to create a gift.
• A highly noticeable notification (in your PM, or backroom) of your favorited, but nearly ending challenges. Time can slip away from a person, and they need an 'in your face' option to remind them.
• A way to cluster multiple submissions/world entries under a drop down list (or this), in the backroom, because some of you are more active than others.
• A way to transfer submissions into challenges, in the event that right after you post something like, I don't know- a Star Trek wallpaper? And someone makes a Star Trek wallpaper challenge the next day, and now you're angry; flippin' everyone the Klingon Bird and drowning your angst in Vulcan Spice Tea, but you've already gotten a crapload of comments and favorites, and loathe the idea of deleting it or uploading it twice. Though, I'd suggest that there's a time limit for this- so that people will still need to create new things, instead of shoving all of their old crap into new challenges.

(Just ideas. Ramblings of a person up too late at night, and feeling slightly critical.)