Sure we have the prisoner, wicker man and the Generals, but what about Horis, Aset, Wrath, Beelzebub, and even the Beast? We seem to be missing out on all these larger-than-life bosses and in the interest of balance, can finally make use of a game mechanic that has long-since become useless: team cost.
Perhaps the Beast is so cost-prohibitive that he is a single toon team only, whereas the others require careful stategy for a balanced team.
Consider this: remember all these shyte toons doing nothing in the roster like meathead and sandworm? What if the team cost dynamics were tweaked in a manner that accommodated the toons we know and use every day in the same manner, but required new consideration with boss toons?
For example, Beelzebub may cost so much that he can only be paired with 8-12 lowly toons, whereas Asset allows for a solid 60-70 toons? Suddenly players have a renewed interest, not only in bypassed and insignificant characters, but entire subclasses of characters used as boss companions for teams.
There can even be bonus passives when world-appropriate pairs are made with the boss and the lower minions, such as possessed submachinegun with Beelzebub, or sandworm with Horis. Imagine coveting your possessed rifle or oxhead skull all over again, because of some new blistering passive it unlocks with a boss! Even the talismans used might flavor the effect if devs want to go deep with this one.