The developers say they modified Mystery Heroes "to help keep the mode's casual pace intact while mitigating some of the more extreme pain points it's had in the past." Removing perks helps players clock what's going on a bit faster, but it diminishes the fun.
The best new co-op games are those that do something a bit different, offering more than a single-player experience with another player thoughtlessly tacked on. These multiplayer games account for groups of friends all wanting their own role, with a shared goal in sight and plenty of chaos on the path to getting there.