The first season was by far the best. I still liked the second season though, and I did think Sylar was a great villian (while he was a villian at least). I kinda wish he woulda ended up getting the time powers though and gone back and saved the Veronica Mars girl from himself...cause I liked her character.
I ended up watching the whole series over again a year or so ago on netflix. It was still quite enjoyable for me, even if the last season was cringeworthy in parts.
Some characters, I'm just tired of. The cheerleader (hayden) for instance, I hope is no longer a main part of the freaking script. She got sooooo old eventually.
I did like peter. I think the actor who played him was quite good and I have seen him in a few movies since then. I'd like to see him back. I also really liked Hiro in the first season or two. I liked future hiro as well, but now Hiro in season 4 was pretty silly stupid (kid hiro.....sigh). I'd like to see him back.
I do think the best way to continue the series is to focus on new characters with only original characters showing up briefly here or there (Except maybe Sylar heh...who I really want to be evil again).
A whole new reboot, could work, but I would rather just see them call it something else then to be honest, and go in a totally new direction. You can't redo the whole "mysteries" theme about what is going on, how they are connected etc....so a reboot would be silly.
As far as continuing the story, I think that might be hard at this point, it's gotten kinda crazy and complicated. Everyone has so much history, (and alternative history) that it could be a real pain making any of it work. Sylar .....as much as I would love to see him as the villian again) wouldn't make sense as one after the last season.
I really don't see a continuation of season 4 to be honest, that would really work and be a great story. It's not impossible, but...with so much crap writting/baggage under their belt, it would be very hard to overcome.
I do curse the writers strike as Heroes had SO much potential. I still enjoyed the seasons after the writers strike...but yeah...I have enjoyed most hero tv shows even the very bad ones. It could have been SO much better.