Well with a terrible second season that had no focus, eschewed character development and no decent plot lines, no show is going to last no matter how good of a start it had and therefore, Heroes fell. It would seem that the untimely disruption of the writer's strike that was taking place, played a part, finally bringing what could have been one of the best shows of the decade to its knees. Eventually this sum of negatives took its toll and with only a slightly improved third season, we all knew it was too late for any hero to save this show.
BUT...
Redemption could be on the cards people! Heroes will be returning in a 13 part spin-off feature.
RIP Heroes 2006 -2010
The Rebirth: Heroes Reborn: 2015
One note for the writers and producers - STOP killing off the most interesting characters!