like
-6v6 50 level
-6v6 25 level

-3v3, 100 level
battles

Hello, adding more battle formats isn't really a problem but outside of friendly battles we do not plan to add any new formats at the moment.

Is this what you are suggesting or are you talking about new ladder formats?

Its all your choice to make ladders for them or maybe some prizes for that battle types. By this, every player can chose a format to make their own team for that format and struggle in that league. 

For example, little cup.
https://www.smogon.com/dex/sm/formats/lc/
in little cup every player has 5 level pokemons

 

Advantages for game:
-Having different battle leagues with different level limits, makes almost every pokemon valuable. Every pokemon good on some different thing. 
-Different players with different purposes can aim their way by their choice in any league
-Competitive players dont have to leave the game when they get bored. They can enter to different pool