I really hope not. I mean yes over the years Heroes has had it's problems but every show does. There's no such thing as a perfect show but there is such a thing as a super demanding fan base that expects perfection and holds the show to rediculous standards that were set during the first season.
I don't say the show is perfect or that I follow is blindly. I see the problems and am not afraid to be critical of the show (I don't know about you but the episode that aired on the 11th of this month was probably the most boring episode in quite some time) but the fans set themselves up to disappointed. The demand so much of it and because of the structure of the show, only plotting the show out season to season and not on a larger long term scale, they sometimes seem to be swayed by fan opinion (because if history shows us anything the fans certainly known what they want and never change their minds or flip flop all over the place

). Way back in season 2 if we had all just calmed down a bit and tried to enjoy the show for what it was not hold it up to season 1 so religiously or hold every tiny element under a microscope I think it would have held up much better not only in terms of fan opinion but structure wise.
I really hope it gets a chance to redeem itself during one more year. I won't say I want it to go longer then that because they would really need to get back to long term thought out creative thought out concepts they seem to only be able to come up with for Sylar (since the start actually) and on occassion some of the other characters.
***EDIT***I hope not because I just read this!
http://blog.zap2it.com/frominsidethebox/2010/01/nielsen-to-add-online-viewing-of-tv-shows-into-ratings-number.html According to Variety, "Nielsen intends to introduce a service that will combine TV and online viewing of shows into a single rating." This is in response to network executives pressuring Nielsen to find a way to factor in online viewers to their ratings.