Just had a thought! OOPS, LOL.
Everyone has 3,4 and 5 star heros ( well maybe not everyone but you know what I mean).
Why not create new 1 on 1 battles much like the event quest where for example a raid battle using only 3* heros and another using only 4* heros and so on.
So you would have something like rare raids, epic raids and legendary raids. You would 3 different cup types one for each.
The same could be applied for new AW battles using only one star type hero by all players.
This would make having all these extra heros we first got so much more usable and bring a whole new interest to the game.