Number Two in what?
In the 'Holy JUMP Trinity', what with One Piece being #1 and Naruto being #2, and Bleach '#3'.
I think a lot of people are missing the big picture here. Kishimoto's finally beginning to show that he knows what he's doing, even if his pacing has been terrible in the past, the plot is actually forming intelligently and based upon characters' actions, which stem from their personalities. Naruto has matured, he understands he can't just HULK SMASH tables and act likely a baby because he's not getting his way like a certain shadow lord we all know. Before he charged in–like at the end of Part I--punched and then asked questions, but that didn't work, nor would it heal the world in the future if he did so against Pain. Naruto's entire journey up until now has tested and redefined his ability to make changes. I dare say he's making decisions the late Lord Third would have made.
Sai, as my instincts tell me, while certainly doing his best to understand what it means to be human, has recognized that Naruto likely wouldn't take back this so-called 'burden'. The promise he made, not only to Sakura but to Jiraiya, has only made him stronger, and it's continued to push him ever closer to being Hokage.
I think readers he frequent boards are just plain bitter, far more so than they should be over a fictional story. While it's taken far longer than any of us would have liked for Kishimoto's 'grand master plan' to unfold, when one actually goes back and look over the story again as I have I think you'll definently have a different opinion.