So, basically, the whole deal with the eclipse was to basically show not only who these characters were and what they could be but also give them insight to themselves. Peter realizes he doesn't need powers to be a hero. Nathan concludes that the world can be a better place if the "right" people had abilities and that his father is right. Claire comes to value her abilities and that her dad can't always be there for her. Hiro realizes, with the help of the creator of Robot Chicken at the comic store no less, that he is an inspiration to others. Daphne realizes, with Matt's help, she doesn't have to run away from her past. Suresh realizes that his chance of having a normal life (and with Maya no less) is gone the moment he injected himself with the formula. And Sylar not only begins to understand that he's been lied to about being a Petrelli (God, I hope so) but that, deep down, he's a killer by nature.
Even so, this whole business with the eclipse was pure filler. Granted, it was basically a macguffin for the characters to understand themselves but that's all it was, a macguffin. Also, considering how there's been total solar eclipses before, why is it that Arthur and Angela never knew about it effecting their powers before now? Wouldn't have they seen this happen first hand in the past?
Not that there wasn't some good stuff here. Hiro rescuing Claire's family from Sylar and Elle was all kinds of win and a reminder of the show's past greatness. Likewise, I kind of dug the whole metafictional subplot in the comic store with Seth Green and Brecken Meyer and how they're treated like sages by the "characters" from the 9th Wonders comic. And to have Sylar kill Elle by the end--well I certainly thought she was the mother of Sylar's baby but I guess that definitely out the window now. And of course, HRG finally gets to be the badass we all remember him to be this season.