An idea how to improve ARURF
Make the matchmaking respect the number of champions a player got unlocked. For real, I encountered so many ARAM accounts that I gave up ARURF and played a couple of normals instead.
How I know they were ARAM accounts? A group of players with matching tags/nicknames somehow flashing lvl 6&7 masteries of the URF powerpicks in what is supposed to be random mode. In like almost every game