Nothing like having an entirely different set of abilities would, and even at the time, the differences for some classes and specs was so minimal it literally made no difference which one you chose.
The differences coming up look minimal on paper, but so did BfA when they said “An iLVL upgrade is an upgrade” and tried to tell us we could customise our classes, which was never the case, the DPS and survivability differences was a lot more than it looked on paper.
Looking now at corruption and everything BfA has brought in, the right corruption effects and minimal negative corruption, the right rank THREE essences (that’s right, ranks 1 and 2 are nowhere near as good) is the difference between 20 tanks clearing through mythic Nya vs. a normal raid group struggling.