Fans got tired of hearing about the superboy punch that changed reality. Basically with so many writters stories started to conflict.
The Red Hood is one and Wonder Woman is another.
To solve the problem without using the super boy punch that ultered reality they decided to recon everything.
The biggest problem with that was they just finished a big batman storyline and a big green lantern story line. They just went through the trouble of making Jason Todd, darn too many robins. I mean Dick Grayson into Batman and the whole white lantern story line with all the differant ring factions.