One in the Chamber was one of my favorite game modes in the original Black Ops. It was designed to be tense and make players pace themselves, having to be accurate with their shots. Not only that, but there was also the fact that if you lost early on during a game, you'd lose whatever amount of points you wagered, which added to the tension.
But having just played One in the Chamber in BO2, it seemed that the UAV was on all the time, which seems to be what happens in all of the old Wager Match modes now. That plus the efficiency of the combat knife in this game makes it so that players are just mindlessly running all over the place in the direction of the red dots on their radar. In the original Black Ops, the UAV only turned on when there were two players left, which I think was the best way to do things.
To be fair, I only played for about 10 seconds before quitting in disgust, but have they actually removed what made One in the Chamber fun or am I missing something?