What you are asking is a Hearthstone-like system where to “disenchant” heroes into “dust” (we could use other terms here, like descension and hero points) and once you got enough points you’ll be able to “craft” (summon) the hero you want, with different cost.
On Heatrhstone you could disenchant x4 card and craft x1 card with the same rarity or so:
- to craft x1 legendary card you need to disenchant:
- x4 legendary or
- x16 epic or
- x80 rare or
- x320 common
You could try to propose it to the request thread but I doubt that this would follow SGG’s business model 