Riot changed its mind
Earlier this week Riot decided to block any pro League of Legend player from streaming any competing MOBA. Riot has now decided to reverse this decision, and players can stream any game they wish.
Riot says that it originally decided to block what pro players could stream based, because competing games were trying to use popular League of Legends players to promote their games by streaming them. Riot will be altering the complete ban to more accurately reflect the original intent, which is to control how players are used to market other games.
Good for you Riot! I think this is the right call. It's what the fans want to see, and it's what the players want to do.