The problem with Heroes is that they don't know how to resolve a storyline. It's almost like they just come up with a cool idea, and just throw it in without worrying about how they'll ultimately resolve any problems it creates.
That and they can not get the characters to do battle in the finales. You build up Peter and Sylar as two powerful beings all season 1, and then they barely fight. What little fights occur happen behind closed doors so they don't actually have to bother showing us anything. Like Peter/Sylar in the future during season 1, and Sylar and Nathan in Season 3 with Claire looking through the keyhole or something.
Superheros are meant to fight their arch-enemy, and we're supposed to actually see it, that's the pay off for building up the tension between them.
Season 4 needs to come out full steam ahead or it might not even last a full season.