I think so. Also stiff usually means working realistically.
You have to have a different standard for the big guys. No one over 6'8" is ever going to be able to work like Angle, or Brett. But, Undertaker was fantastic for a near 7 footer. Very agile, and would take good bumps as well.
I mean Taker was A stiff, not that he worked stiff.
What was so quality about Michaels and Benoit? I clearly don't understand what makes a technically high quality professional wrestler. Would you say Sexual Chocolate Mark Henry is top 5 GOAT, or merely top 10?
Selling (both of individual spots and in terms of consistency), spot quality, pacing, story-telling within the match, transitions (notice how some spots require one guy to do nothing for an implausibly long time or generally behave stupidly--good transitions are the opposite of that), variety. You don't have to break it all down like that, but if you watch a lot, you'll notice that some guys' matches are always fun to watch, while other guys suck.
Even though Hogan was terrible, I think he really illustrates the storytelling aspect with something he used to do. In a lot of his matches, he'd go for the bodyslam on the fat guy, and hurt his back, maybe once or twice in the match. So then when he hit it later, after some additional desperation and motivation, it would seem a lot more meaningful. On its own, it's a pretty lame spot, but within the context of the match, it would seem cool. That's like the most basic, simplest kind of storytelling. Michaels was also good at developing spots like that, but the developed spots would be better and the development process would be deeper. The Liger/Sano series was a great one to see really well-developed spots (developed over the series of matches rather than just in one).
Misawa had a spot that was developed over multiple years. Super dangerous move that he hit and then retired. Then, later, in a really tough match, he's pulling out all the stops, but can't get the finish. He makes the apparently difficult decision to go for it again.