Hmmm...
https://uploads.disquscdn.com/images/0b87f5d8b9de1818826e5052fde30b9a6e9c574b590332cbfec45b43c3146667.jpg
Could this mean that there are going to be more arcade skins? Like a 5 man team of arcade skins and a 5 man team of boss skins? If you look at the bottom where the VS is you can see that there are missing icons for champions.