Injustice Mobile: What if the Boss subcategory were to be expanded?

WASDuk's Chris Patton shows off concept art for DC Characters that could be used to expand the Boss class in Injustice: Gods Among Us mobile. Currently, Boss Solomon Grundy is all alone:

"But, why don’t we have more Boss cards?

Darkseid is theoretically the biggest bad in the game until we get a Yellow Lantern Superman or a Trigon or an Atrocitus. However, none of those characters have made huge blips that foreshadow playability on the radar yet. On the other hand, Darkseid does have a Boss form in the comics, though he’s not in the platform version and we, therefore, have no idea what other skins of him will arise."