During my competitive years, I wouldn't settle for anything less than ranked Summoner's Rift, 5v5 (Dota). But as I started to fill my schedule with other games and responsibilities, I needed another mode that I could dedicate a shorter amount of time to. I still wanted to play League, but I didn't always necessarily have an hour to an hour and a half to dedicate to it at all times.
Thankfully, Dominion came around, which is essentially a twenty minute "capture the point" mode. It's an excellent non-competitive gametype that helps players get that small piece of MOBA combat without requiring an insane time commitment, or even a higher understanding of play. But sometimes, it wasn't enough -- I wanted more lane based play, but on a smaller scale -- that's where All Random All Middle comes in.