Only one thing leapt out at me:
The new Weapon sizes?
BLAAEEECCCH!
The way it was described make me think I'll have more trouble with that than I EVER did with Attacks of Opportunity!
However, my opinions and Monte's have diverged on many other points. His dislike of 1 hour to 1 minute spells I enjoy, because unlike him I've seen rampant abuse of those in my games - people empowering them, extending them, making them last for OVER a day's time, and generally players acting like they are ENTITLED to a 3-point boost to all stats for 24 hours. As much use as they got, I might as well have abolished the spells, and just gave each player a 3-point stat boost to all abilities. Now, they give a tangible benefit, they last for one combat or two subsequent combats, and they aren't active all day.
Also, too, I like the facing - long-facing creatures used to give me fits with the 5x10' set-up - flanking, attacking creatures from one side to the next, etc.
In all, I appreciate his article, because it gave me some good in-depth perspective. (It also made me shed a tear for the good ol' days when Peter and Ryan used to run WotC and the Tabletop dept.)
And hopefully, he is right, and we will all come out stronger for the revisions.