The (relatively) new show Heroes has three major sins:
1. Not enough budget. If you can't do convincing special effects, then there's not much point in doing a supers show, unless everyone has lame powers.
2. Too many lame powers. This also is connected to another problem: too many characters. The best unnecessary character/lame power is a woman whose super-power is having an alternate personality take over her body. The alternate personality has no powers. If I end up in a comic, I hope my power doesn't turn out to be a mental illness.
3. Soap-opera story that moves nowhere. With all of these characters, the show has to spend a bunch of time reminding you who's who in each episode. With only 44 minutes, there is very little time to deal with three or more stories. Also, the stories they tell are kinda lame. Shows about supers are supposed to be about Supers, not lamers.
There is one other sin: they used the "silent child ominously being silent and revealing something important". How lazy.