On July 10th, 2013, Valve finally managed to release an objectively bad update for Team Fortress 2. They completely and utterly nerfed the so-called Polycount Sets, as well as several other, minor sets. There was no attempt at compensation made for this: Each polycount set had its benefit replaced with a cosmetic effect: leaving a "calling card" on one's victims, except for the Saharan Spy, who got a rather odd-looking sand whirlwind effect with his taunts.
I am particularly disappointed with the removal of the headshot immunity from the Croc-O-Style Kit, especially since the ability to perform headshots was not granted to the Sydney Sleeper. The set was completely fair as it stood: A sniper wearing Ol' Snaggletooth could be immune to headshots, but only if he also bore the Sydney Sleeper as his rifle, removing his own ability to perform them. (Darwin's Danger Shield and the Bushwacka were also required, which only lends more credence to the notion that they were balanced.)
I suppose that I'm particularly miffed about this because I spent ages accumulating what my calculations show was the equivalent of 73 weapons to craft the damn hat, only to have its benefit completely removed shortly after I got it.