My idea was :

The new items are Ruby's
You can gain 1 Ruby by playing 10 Multiplayer Battles
For 50 Ruby's you can open an Ruby Chest
The Ruby Chest contains :
30 % Mythical
60 % Legendary
10 % Epic

In this way people Will want to play more to get the Chest so they get an reward for playing a lot.

so the real fans get an reward for playing and the other people dont

Thanks for listening.