Right now the Maingame helps the Conquest mode progress by leveling the hero in the Personal Hero slot. And i think it would be neat for the Active Hero to also help the Maingame by gibing some sort of buff. For example, all suport heroes buff Elixir, Assasins buff Coin value and tanks buff the rate at which enemies apear. Maybe the buff amount is determined by the Starlevel.
#Personal Hero should give a Maingame Buff
rustic pagoda
mossy island
too simple, as proposed it would be quickly determined what class is meta and all that would do is retrict what heroes optimizers could use for their active heroes