It appears as if the real purpose of 6.0.1 was to reset the User Reviews at the Mac App Store. The scathingly accurate 1-star reviews of 6.0 have now been diluted into the "All previous versions" pool, where they're defanged by their proximity to the glowng reviews of version 5.
Apple pushed the reset button on reviews. Only reviews of 6.0.1 are shown as current. Brilliant!
And what sparkling new innovations did Apple implement in 6.0.1? A customizable toolbar! Can you imagine? The "new" transitions? Blinds, Confetti, ... In short, nothing that wasn't already up and running in 5.3.
The genius is that whenever the 1-star reviews get too heavy, Apple can ladle out a few more 5.3 features and pound the reset button. Stripping features in 6.0 so that they can advertise them as "new" in incremental updates sets a new low in software develpoment. I don't even think Microsoft does *that*.