Look, I can't speak from personal experience about Coils. I never did them. You had the same strategy as the guide. Cool. Doesn't mean it was the only possible way to play.
No one is claiming that Aero + Thunder being a DPS gain is anecdotal. In fact...
So already, they didn't say all you said was based on personal experience. They said most.
So sure, Aero 1 and Thunder is a DPS gain, but clearly not every WHM that did Coils during progression had Thunder selected as a cross-class skill. Some deemed it to be less important than other skills they could have taken.
I don't see why it matters the exact date they beat it. They said that, like you, they did progression and in the same gear as you. So whether you beat it first or they beat it first, honestly doesn't matter. They don't seem to be arguing about whether your way was most effective or not. They're saying that your experience is your experience, not theirs. They did it different. And you both beat it. So there isn't only 1 right answer. To see who beat it first is just a pointless attempt at flexing.
Whether something was a "necessity" or not, who knows. But I'm just saying, if someone could beat the same thing you did using a different method, doesn't seem much like a "necessity" to me.
And truth be told, as a bystander to this conversation, it seems more like you're looking for a fight than a debate. Don't take this the wrong way, but you're coming off very.... for lack of a better phrase, high and mighty. Like you're looking down on others for having a different method. To me, it reads as "well, I'll have you know that I beat it at this time, I was one of the first to beat it, and my method is the same method that the people who wrote the guide used, so it must be the only correct way". Whether it was the intent or not, that is definitely how it came across to me. Take that how you will.
And I'm saying this as myself; Aero puts all your GCD skills on cooldown. So yes, keeping a DoT up is a DPS gain over the entire course of the DoT being up, no one is arguing that. But choosing to cast Aero 1 and Aero 2 over Aero 2 and Stone 2 seems like a drop in DPS as you took that GCD time you could have used for a Stone 2, and continue to lose GCD time every time you reapply.