Long ago I enjoyed a game by the name of StarCraft. It was good. When I heard about Ghost coming to the Gamecube I was more than excited to have a more hands-on and more personal experience of the world created by Blizzard. As with any great amazing game, it fell to the trash heap along with Mega Man Legends 3.
Riot could and should try their hand at this idea, let you take several champions to explore an open world environment as Ashe, as Master YI, as Teemo outside of the fields of justice and maybe even within it. This would provide a great way of giving players the lore they want while at the same time taking a less competitive stance to each of our favorite champions.
They could:
There's going to be pitfalls of making unique and interesting gameplay, yet they've done a fine job of making fun champions to play in their game, in my opinion. Personally, I'd rather it not be an RTS as it would seem pointless given that LoL is already like one in its gameplay, you'd just be adding a bunch of extra sub units unless it'd still be minions, super minions, cannon minions, etc.