How many times can you reissue the same designs with a new number and call it innovation?
I'm quite sure if you interviewed the Mizuno product manager, he'd tell you numerous things that have changed. Same as the Taylor Made product manager would about Rocketbladez to Speedbladez, or the Callaway product manager from XHot Pro to X2Hot Pro. Doesn't mean any of them are lying, but also doesn't mean each is a totally new design either.