Okay, I read the whole thing -- first pass anyway.
The first interesting thing is the Weapon Mastery -- which is additional properties on weapons for those that have mastered those specific weapons. I'm not sure I'm a fan, because it effectively becomes additional status conditions to track for the DM. For example, did the ranger hit the critter with a bow? Slowed movement speed. Vex looks like it would be super useful on a rogue -- just chain sneak attack for days.
I kind of like what they're trying to do with the monk to try to make them more interesting. But I think that they need to boost the power of the effects, or boost the number of totally-not-ki points.
Everything is so hamstrung with the backwards compatibility issues though. It feels more and more like this is 4e's D&D Essentials rather than a 3.5e update or a 5.5e update. Changes for the sake of change (to sell more books) rather than changes that improve the game. Still going to buy it though. I'm a sucker ;)