In terms of overall successes, the biggest one for HeroClix was Seth's approach to character design. There was a bit of 'conventional wisdom' from the early marketing department that you had to do only Tier 1 characters, and Seth lobbied hard to buck that trend. He also changed the game from a first strike and/or turtling game to something far more nuanced and strategic.
Jason "Brother Magneto" Mical, HeroClix World Interview (2009)