Where are my new heroes?

Is there any way the developers would consider weighting which heroes you get? Every time I buy a new hero, I don't get the chance to play with it. I purchased Rumpelstiltskin, and in 20 games, I've only had the opportunity to play with it once. Same with Mira. I feel like they should let you play with the new heroes more, especially if you've spent gems on them.