5'8" ain't a problem for 29" now... with hydroforming of the top and down tube they fit much better.

The reason to get a new ride is just that, it's new. Technology and engineering changes(not NEARLY as fast as marketers claim). If this is a difficult concept for you, i don't know what to say. Have you never purchased something new? Commie. I have also found replacing parts to be at least 1.5x more costly as most major bicycle manufacturers get steep discounts on forks, shocks and drivetrains - not to mention tools.