The Fan Art tab is an amazing idea!
######Link for the lazy.
I was browsing through the page, and went to click on the submition page to see how it worked. There is a Fan Art License agreement, and after reading it it has me really hopefull!
"License. By submitting artwork through this website (the “Artwork”), you grant Riot Games and its agents, affiliates, successors, licensees and assigns a perpetual, irrevocable, universal, nonexclusive, fully-paid and royalty-free, sub-licensable and transferable license to all intellectual property and other rights in or to the Artwork to create derivative works based upon, modify and otherwise edit the Artwork, and to copy, sell, publicly display, publicly perform, exhibit, use, distribute, and commercially exploit the Artwork or any such derivative work or other portion, derivative, or modification thereof in any manner and for any purpose..."
This may sound a bit extreme and specific, but if I'm interpreting this correctly, Riot set up a way for users to submit artwork that can be used in actual produced game content (legally). Now there won't be any more discrepancies about stolen ideas or disarray about ignored ones.