Who said Lebron was going to be the second coming THIS YEAR? Nobody. He's matched Jordan's rookie numbers, so why would you think he's going to falter and become a mediocre player? There is absolutely nothing to show that he won't become one of the greatest of all time.
Singlehandedly save the league? He doesn't have to, but he's already singlehandedly saved Cleveland. Yea, Boozer had a great year too, but make no mistake that the franchise made more money this year than any year since Mark Price (screw Daugherty) because of Lebron. And yes, being number 1 in jersey sales does mean he could singlehandedly put the league on his back. He's already making them TONS of money.
I don't know what kinda fucked up people you listen to, but I don't remember anyone expecting Lebron to average at triple double, although he came closer than anyone in the league. He may have been hyped beyond all belief, but he's certainly met those expectations. His numbers will only continue to grow. He's not even 20 yet and you call him over-rated. There's just no pleasing some people.