In December, two of my favorite bloggers wrote about their experience playing with Freezing Arrow. In short, neither Big Red Kitty nor Chain Trap like it much. I like it more than them, and I think I can explain why.
But first, I do have to agree with those who say that crowd control is in general not much wanted in the current endgame. There's a brutal simplicity to the heroic instances and the raids I've done so far (Archavon, Saltharion, and the first three wings of Naxxramas): tanks use a lot of AOE, and damage-dealers go for single-target or AOE as their specialties may be. There's more room for mages' polymorph and paladins' repentance to make a difference than any trapping hunters can bring to bear.
Nonetheless, there are some places where it's handy, and times—helping gear up guildmates who aren't yet powerful enough for AOE tanking to do it all, for instance, and when Tivara's out questing on her own.
Freezing Arrow can be used two different ways. If your hunter shoots it so that it lands near a target, it'll freeze the target immediately and rouse all the target's neighbors to hostile action, just as if they were pulled by anything else. But hunters can also put down a freezing trap a bit farther away. And this is what I do with it. I'm not pulling with the trap, I'm putting it down so as to catch someone at the back of a bunch, or off to one side of it.
Used this way, the freezing trap behaves like any other. The trap goes down, but nobody's yet pulled, and the regular countdown applies. I wait for at least 10 seconds, so that Tivara can put her next trap down before the first one wears off, and then pull. Voila, freezing fun at a distance.