Since I know the guy who does these effects, I can say, for one thing, that the flames being done in Heroes are all real elements composited over the action, not digital simulations. The flames along the bottom of the frame were actually, I believe, an in-camera effect. No need to do it digital when you can just shoot it on set. I'm not saying that they don't stand out to you as "not quite right," but it's not necessarily because they're "CGI." But I will agree that I never found Meredith's use of her power nearly as interesting as Flint's. All she ever seemed to do with it was set her palm on fire to prove a point.