Whenever you want a heroic dragon, you always have to win a heroic race or get to lap 12 or 15, however here are my ideas on other ways to get heroic dragons,

*collecting 1000 heroic orbs
They should be rare for extra hard work

  • fighting many times against tough dragons
    They might be max but for nerf,they are not gonna have any stars.

*special missions
Just like the missions for getting your guardian tower, you have to do missions to get the heroic dragon, the missions will probably be hard.

I suggested these ideas because I'm getting bored of races(they are still good though).