I am in total agreement with almost everything said in this article.
I am extremely happy to hear that DCs don't scale with level, as that never made any sense to me at all. Why should a door be DC 10 to break down at 1st level but DC 25 to break down at 30th level? That makes absolutely no sense and means that all the level up bonuses the character gained don't really mean anything since he's not actually any more likely to succeed at something than he was when he was lower level.
I also like how, with fewer bonuses, those bonuses are more precious and meaningful. I like how a 20th level wizard, who has probably not really spent any time training with weapons, doesn't need to get a +10 to hit just because he's higher level. Despite that, the wizard can still pick up a weapon and at least try to use it with some chance of success, since he might only be +5 or whatever behind the fighter. I also like how this allows DMs far greater flexibility in what monsters to throw at the players. A mob of peasents can still threaten a group of high level characters, rather than being a trival concern.
The only concern I have is all the talk about hp and damage bloat being the primary way characters advance. It seems contrary to many of the goals they discuss when talking about flatter math. I'm not saying that characters shouldn't gain any hit points or damage as they level, I'd just like to see that part of the math be flatter as well. A mob of peasents might be able to hit you, and be a potential threat that way, but they're still a trivial encounter if the wizard can wipe them all of the face of the map with an AoE spell, due to their low hit points and the wizard's extremely high damage.
