EW has a great interview with Pushing Daisies regarding his return to “Heroes” and what exactly went wrong witht he show:

It became too dense and fell into certain sci-fi trappings. For instance, in the “Villains” arc, when you talk about formulas and catalysts, it takes the face off the drama. And I think the goal for everybody is to put a face back on the drama. You have to save something with a face; otherwise you don’t understand what you’re caring about.