League of Legends Arcade Mode?

So this is just an idea that I personally believe could bring more players to the game and bring old players back. In custom games all you're limited too are Treeline, Howling Abyss, and The Rift. Little known fact there was also a 4th map. It was used for the game modes: Dominion and Ascension. Personally some of my favorite game modes. What I'm suggesting is an arcade mode seen in other games. But only allow it in customs. So every past game mode URF, ARURF, Poroball, Dominion, One For All, Nexus Blitz, etc. all available in Custom Matches. But if you have a group of friends to play with you these modes could become even more fun. This would be a big undertaking for the Riot team because of game balancing and all so I don't have Incredibly high hopes. If you think this is a good Idea please tell me because I think it is and i want to be justified