No, it's absolutely correct. There was a clear direct inverse relationship between tank stance uptime and percentile. If I could identify two things that a player could change that would have the single greatest impact on their performance, it would be using STR gear in place of VIT gear (outside of 3.2-3.3, and when you were allowed to do so), and turning off tank stance. (No, fixing your Scourge uptime just pushed you from 80th to 90th. Even you did it correctly with tank stance on, your damage output would still be terrible. Always start with the basics.)
It's worth remembering that with tanks and healers, there was a subset of the playerbase who either didn't understand or believe how we used stances in optimization. "What do you mean turn off tank stance when I'm tanking? Won't I die? Won't I lose aggro?" When in reality, neither of those things were likely to happen, and you just had to get over the psychological barrier to doing so. Now that the damage penalty from tank stance is gone, there's one less barrier to entry for making those players competitive. So now, that same player who was unintentionally hampering their own dps by keeping stance on, is suddenly performing just as well as you because they know how to press the 1-2-3 buttons like you do and have half decent ping. And you're just not as good as you thought you were.
And please don't tell me that enmity management without stances required skilled play. It mostly relied on raid comp, and there were always work-arounds. Snap enmity did take some fight knowledge, but the last time that was interesting was the T13 adds. Equilibrium trivialized add pickup. And the only place where I'll buy the 'stance dancing' argument from a mitigation standpoint is if you're doing a tougher fight at a lower gear level, like A4S/A8S. Anything from Creator on into Stormblood most definitely did not require stance, and it really was just as simple as turning off the button. I can't tell you the number of people who I've seen have massive jumps in their performance just by trying it out. It's really that simple. The truth hurts. Sorry not sorry.
If you want to bring back some 'good ol' times' unnecessary convoluted archaic rubbish to create a skill differential with, bring back directional autos instead. They were at least somewhat entertaining and involved some degree of actual mechanical skill. I miss strafe lock gliding.