I don't think his reasoning behind freezing is correct; most of what I've previously read suggests that freezing is only a useful trick for bearing damage. If the hard drive is making a rattling noise while running, and then stopping, it likely has a bad bearing, and freezing it for a while (or running it cold) can coax the gimpy bearing into running a little longer. However, you're probably not going to be able to get the entire drive image off of it, so pick and choose what's really important to you.

In the event of an actual head crash, you're usually screwed. If the head crash left a stripe all the way around the platter, the head likely won't seek past it. (I don't know why; it should be able to, but it doesn't -- I tested this recently on a Toshiba drive.)

Head crashes seem to have a tendency to occur close to the spindle, and if that happens, the data on the drive is completely irretrievable.

Occasionally the armature will develop a mechanical fault and will collide with the edge of the platters when the drive powers up. If this happens, you can usually either "adjust" the armature slightly, or replace it with an armature from a matching donor drive.

There are a few other tricks and things too, but those are the most common for internal failures. Sometimes just replacing the logic board is all that's needed -- you have to be able to diagnose what's wrong with the drive. Simply sticking it in the freezer isn't likely to do a darned thing for you.

And I'm a little skeptical that this guy has ever even cracked a drive open. They don't have a "bunch" of platters, they almost always have 2.