First of all, I really like the idea that's been floated here of Masterwork Weapons. When the PHB had Masterwork Armor, my first thought was, "well where are the weapons?" I'm surprised they weren't already in AV.
On the Expertise Issue, I think that we might be blowing this out of proportion just a little bit. In heroic games, this is a good feat, and sort of a no-brainer for classes that don't have a lot of specific feats targeted at them. For classes that do, the feat really isn't that spectacular until you get to that +2 bonus at Paragon level.
I play a Drow Rogue in Living Forgotten Realms, and I'll be choosing to use my Dexterity for Base Attacks long before I take Expertise. Why? Because my typical adventuring party includes two warlords, and they both have the ability to give me bonus attacks, which I ignore because the difference between my strength and dexterity on a to-hit roll is _5 points_. I will eventually pick up Expertise, about the same time as I would have bought Nimble Blade, but there are so many feats that are more useful to a heroic and early paragon Drow character that I'll use first.
A +1 bonus to hit at heroic levels is nice, but it's also not the end of the world if I don't have it. For other types of characters, the feat is much more useful: I'd take it before any of the situational +1 bonuses, especially since it will stack with them.
Is this errata? Sure looks like it. Is it bad design? I'd say no, but I'd also prefer it if they would have introduced Masterwork Weapons/Implements instead.
Just my $.02.
--Steve