As I said in another thread, you could easily make opposing regions, like in Red you can as a player choose an all blue team. As a mystic region, you can use say Daemons. For Divines you can use Dragons.
At least that way there is no same team vs same team. However it needs a proper look. Blood Frenzy is broken content as is too. It might need bonuses based on troops you bring rather than the idle 50% stat boost that permeates everywhere.
Who will chose a fight vs a 50% boosted Stellarix? It’s a 1 cast wipe for most of the player base.