There's an Exclusive Interview with Valve's Robin Walker on CommunityFortress chatting about Team Fortress 2 (thanks Shacknews). One of his answers indicates Valve is still evaluating how to deal with item unlocks: "I think we've learned that the random drop system is only good for some types of things, like the rare cosmetic hats. It's good for delivering items to newer players over time, so they're not swamped with choices when they're starting out, and they're not required to grind achievements to get them once they reach the point where they want to start making strategic choices. For competitive players, it's obviously a bad way to deliver items. At the very least, future packs will allow you to use achievements to get the new items, but we might move to a mode where we just give them to you. As part of our goal of supporting tournaments more, I think we'll probably add better tools for them to control exactly what players can & can't use within matches."