Fast forward to the Spy vs Sniper update and Valve has introduced a new system. Gone are unlocks via achievements; arrived are unlocks via random luck (or so it seems). The new system:
For the last number of months we've been working on using the Steam Cloud to store a player's inventory. With that finally in place, we were able to deploy a new system focused on the giving of items to players. That new system watches the amount of time that players are playing TF2, and gives them a chance to find items at regular intervals. They aren't guaranteed to get the item at those points, but they have a pretty good chance. We based the system on granting items on the amount of time played because we don't want players to have to do weird things like join achievement grinding servers to get new content. Basing it off time also has the benefit of ensuring that if you play a lot of TF2, you're going to get more items than players who don't.
However, this has spawned a new type of cheat. Players are filling up cheat servers, going AFK, and after X hours are receiving their items. Whereby, a lot of players who are actually playing, are getting items at a slower rate because when someone actually plays, there is downtime between matches as servers load new maps. There is a slight advantage to the cheaters currently, but honestly, if the items can be attained legitimately by just playing, the cheating isn't as detrimental as within the old system.
Valve has stated the system is suffering from some bugs and they are investigating it. The major issue where players were receiving NO unlocks after hours of play has been resolved.
In the first few hours after the release yesterday, we had some issues that prevented the system from working properly, so that timeframe was not indicative of the system as it's designed.Unfortunately most of my playtime with the new patch was during the affected timeframe, so I do not have much experience with the system to give a thumbs up/down. So far, in about an hour of play outside that window, I've yet to stumble across a single item. Thus, I am ending this post and getting back to the business of bitch-slapping some spies and hoping for random drops. It almost makes me wonder if I'm playing an FPS or an MMO!
Update: After 2.5 hours of play, I have "found" my first item. I died and then a screen popped up stating that I had unlocked Bonk! Atomic Punch for the scout.