a while back there was a system where you could earn letters by acquiring more gems from a character than what was needed to recruit them, you could then use those letters to recruit other characters, I think bringing back that system would be nice as you can only earn that currency by obtaining more than what you need to unlock a character, naturally, it would require more letters per tier with mythic girls costing 5-10 times more than Legendary, but it was a good idea, I wonder why they removed it?