1 star idea
As a lot of people dislike the Sunday arena's because they are basically useless. Why not replace the 2 star crystal with that crystal that has a 20% chance for a 1 star. Gives people a chance to get those they do not have for free. And won't hurt the people that actually want the 2 stars too much. 1 star gains won't be fast. But atleast it is a free way to get them, and will (temporarily) bring back life to those arenas.