Why has there not been anymore RANKED maps/levels added? Getting really tired of Summoners Rift

Starcraft 2 has at least 10 official Ranked maps. Call of Duty has multiple ranked levels. Super smash brothers has multiple levels

There are many many other popular games at the ESPORT level that have multiple maps for their competitive ranked gameplay.

Why not add a few more 5v5 maps!?

Maps could be chosen at random, or have a banning process just like champions during draft pick. Or maybe they could be chosen by vote?

The only flaw in this game is the lack of game play maps.

Here's what i'm proposing:

• Additional maps would just look slightly different (Same Size)
• Lanes would maybe curve different directions in some of the maps (Imagine a map with lanes that had S curves all over the place)
• New Maps would have the same amount of Jungle Minions, and they would be arranged in a fashion that is mathematically identical to Summoners Rift.(Distance between camps, and distance between camps and lanes would take the same amount of steps to walk to and from)
• New maps would have same amount of lanes, turrets, lane minions, and inhibitors. (So that score averages for players would not be affected)
• Some maps might not have a river at all.

The possibilities are endless. Why Can't Riot Games get creative here?