I'm pretty sure everyone has played this atleast once.
It's simply, the collor Blue and Pink on legion and hellborn side random an hero.
Then the rest of the team should have the exact same hero as their leader.
But 6/10 games people don't understand this and mess things up.
They choose a different hero instead.
My suggestion would be, make a game mode where the blue and pink get randomed and the rest will follow automaticly.
I hate that mode, but I think your suggestion is good.
I think it should be just a separate mode, not forcing random. So when blue / pink picks a hero, the whole team gets it. Would be great for devourer wars etc.