In theory, Heroes should not be popular. We are at the tail end of the superhero revival, having exhausted many of the old classics, of course infusing them with dazzlingly attractive celebrities and countless explosions. And the group superpower concept has been done, most recently in the X-Men trilogy and even in The 4400.
Perhaps it is because Heroes very carefully straddles the line between full blown comic book fantasy (X-Men) and a this-could-happen-to-you situation (The 4400). Or maybe it provides viewers with an outlet for their fears of nuclear war, with everyday citizens to saving the world. Maybe it's because there are simply so many characters and storylines that even someone who has watched the first two seasons in five days can't keep track of them all.
But I think I'll go with explanation number four: we don't know who the bad guys are. We have a pretty good grasp at who the good guys are, Claire, Hiro, Peter. But even future versions of themselves are pushed to such extremes that their actions slide into a morally questionable area. So, who are the bad guys? Mr. Bennet? The company? Even Sylar puts on such a good show sometimes that we can really believe he's changed. After all, his conversion into a sociopathic murderer becomes understandable if not condonable after seeing his past. Basically, this show is not High Noon. There is no sheriff and no outlaws, and the only thing more slippery than the morality of the characters is the future itself.
Of course, there's always the possibility that high Heroes viewership is a direct result of some sort of government conspiracy to keep track of all of us. In other words, the only bad guy here is the Nielsen ratings.
Season 4 begins with two-hour premiere on Monday, September 21 at 8/7c.