for me personally the site has been kind of weak without the exciting learning topics. it would be more exciting having topics like "why is this piece/melody so good?" or "can you make a variation as good as this original?" , or "where did my melody go wrong?", etc. things that we could learn from.
regarding these competitions, i guess you can also add something like: "make a piece illustrating your first love", or "a piece to make a child smile" or cry lol. "illustrate (musically) a given picture", "replace the music from a given movie scene", "extend or reinterpret the last good song you heard on the radio" or " 'remix' a top 5 Mtv song"..
i'm not ready for these competitions, i still need more learning related discussions.