i think it should be possible to win with a smart strategy, not only with the right toon. let's take the corrupt general. when he stuns the enemy with 95% (paired with the warrior bomber boy or assassin troll) there is no chance for the opponent to win, when you start the battle. such things shouldn't be possible, so it's more than okay to balance them.
balancing is all about action and counter action. if you do something the opponent has to have an opportunity to counter it, regardless what you do and regardless what team you have. that's an ideal scenario.
take stracraft 2 as example. it's so well balanced so that you can take every race and win the game, if you are good.every unit has a specific counter unit. so you won't have an advantage, regardsless which toons you use it solely skill based. that is balance in my opinion.in an ideal world with an ideal LOTB everyone should have the chance to beat anybody with his toons, as long as his skill is better....