I will assume that you did not fail at reading comprehension and simply forgot what you had said. Let me help you out:
Now try reading what I said again. You list three abilities and I point out that the core ability in that group was Spirits Within. Also, you compare these to a ranged classes level 12 ability as if it were supposed to be on par? I think you are making my point for me.
Yes, you correctly listed the PLD's core enmity generating abilities. They are good, but not great damage. Potency is not the end all and if you think that activating Sword Oath suddenly makes us a viable DPS class then our discussion ends now. No point in going any further with you.
Using a CD on yourself is easy enough to do, you know you have high incoming damage or you want to spare the healer some MP or give them time, whatever. That is a part of life as a tank. What makes Cover so worthless, in my opinion, is how narrow the use cases are. You listed one and it can happen. But why are you the only thinking "Oh shit"? Does not the other tank have an option, or the healer? Suddenly, you swoop in like a savior and completely waste somebody else's CD and shift the healers focus to you.
So, no, it isn't a normal "Oh shit" button. It is a button that needs communication and if it needs communication, then it isn't reactive. Beyond that very narrow chance to use it, when else would you rather use that than something else, like Provoke or Flash? You could Cover a healer who just took group agro, I guess. But then Cover is the bad tank button. It just feels annoying.
I'm sorry you disagree. I don't think 2 or 3 of our 5 job abilities should be for secondary tanking. In practice, we only have 4 since 2 of them are stances. The WAR has no option for DPS or secondary tanking, so I'm not sure why you think it is ok for PLD's. There might even be an argument that the GLA is a better secondary tank than a PLD since they would have many more options for the whole of the fight. That would take some looking into, though.