After sending about 60 TB through the HDDs in the wipe operations, I don't notice any degradation:
Anyway I'm stopping the HDD wiping experiment, since the way I'm stressing the drives, they'll probably give out before the P67 will...
Note that I am not saying the problem doesn't exist; in fact I read one post in the Anandtech forum in which the OP says his/her SATA2 can no longer recognize drives. What I can say is that whatever the fuse on this Cougar Point bomb is, it's not short enough to blow out your I/O controller with certainty after a few days of HDD wiping.
If you have other suggestions I'll give them a try. Don't tell me to raise voltages because I think it's unrealistic to do so. (It's like saying you can simulate long term on a car by exceeding its towing capacity for one trip - the stresses are all different.)