That's not entirely true at all. For the tanking role, you need 3 things
- taunt. Kinda need some form of that for tank swaps. Technically don't NEED need a taunt button, but for the sake of not making the role a fiddly, micro-manage-y nightmare, it's necessary
- some way to deal with in-coming damage
- some way to keep the mobs from hitting who they're not supposed to be hitting
And that's it. Optionally, you can also add party support to the list.
In absolutely no way is it required for every tank to have the same 2 defensive CDs and all the other stuff I listed in the OP. As long as every tank has tools to accomplish the above things, you're good to go. Having all tanks accomplish these things in the same exact way, however, is what I call unnecessary homogenization.
What this homogenization does is rob you of moments of glory, where you are able to use your job's unique traits to accomplish something the other jobs wouldn't be capable of.
Referring to the eras of WoW before its class design got good isn't fruitful. It's disingenuous, because you're referring to the most extreme possible scenario in an attempt to portray what I'm suggesting in a bad light, even though that extreme isn't remotely what i would like to see in FF14. Yeah, I don't want certain tanks to be completely worthless in certain situations, nor do I want BLM's entire rotation to consist of nothing but Fireball. WoW has long since moved on from that nonsense, but tanks are still allowed to have certain niches they excel at, which is what leads to said moments of gloryWoW used to have different classes have wildly different role kits. Do you know how long Resto Druids had to play without a standard Raise spell? Too long is the answer. Paladins couldn't even taunt for a long while. Bosses like Illidan were nearly functionally impossible for any Tank but a Warrior because of Shear and how Crushing Blows worked at the time.
Never did I suggest that what I'm talking about is a massive deal breaker that needs to be fixed ASAP.
What it is is a waste of opportunity