Having gotten a good look at it in the FLGS, some thoughts, on the thought that this is a 4e preview:
* For all the griping about allocating skill points for high level characters, the game still keeps the other gripe about high level characters: rolled hit points. A sacred cow that is stupid and inefficient, adding a variable where one need not exist. Give a bonus for size for everyone instead of the max at first level, which makes no sense since there's no roll.
* The idea of half level plus trained plus Skill Focus is great, and needs to be used more. Add this to combat. Make some UA-style weapon groups and call them skills, and let fighters pick from all of them and wizards from none of them and have defenses work the same way. Let armor have a nerfed armor bonus (+1 light, +2 medium, +3 heavy) that always applies to trained users always and everyone gets DR from it; you might want to keep the Reflex Defense skill away from classes that have great armor (like fighters). This is the Core Scaling to go with the Core Mechanic. Doing this makes the epic-level phenomenon of attack bonus outstripping armor class go away.
* This isn't a criticism of the book per se, but can Wizards make a full-size version of the character sheet on its site, instead of one at the size of the book? I understand the issue of including a full-size one with the book, but no such limitation comes with electrons. Oh, yeah, and it's ugly too.
* Can someone playtest the Damage Threshold? I'm intrigued.