This doesn’t negate my point though. See:
If you look at any of the links Zipzo provided in that old thread, you’ll see more than a few posts by people disregarding the usefulness, or simply doubting the usefulness, of powershifting. Still others misunderstand how or why it worked certain ways even during TBC’s lifetime.
Powershifting was a known thing, but it wasn’t a widely known thing. If you were the kind of person to crawl forums and read EJ and similar, you probably knew about it as a DPS method. Also note that powershifting refers to both the specific usage for DPS and the macros so many of us had just for general PvP use. I had a cancelform macro in Vanilla, but I never really bothered with trying to utilize Wolfshead Helm or Furor for DPS until TBC after reading a lot of the EJ stuff.
Sorta muddies the waters when looking through old stuff when some talk about powershifting for DPS and others talk about just using shifting to break roots/snares instantly.