Dear citrique: I'm not sure if you're new to the mage class, condescending, or if I expressed myself poorly. All of what you posted is true (likely), but it is UTTERLY beside the point. That you fail to see this just reinforces my assumptions about the state of mage theorycrafting in general.
Of course we do have an understanding of how to play. People are performing, in every specc, and I have no doubt that it is mostly sufficient to do exactly what you've written. It's as nice and easy as following a guide on Icy Veins. But these simple answers simply aren't enough, and wouldn't have been worth anything but an infraction back on the EJ-forums. Because this "knowledge" we have is nothing more than basic guesswork. It's by no means useless, and if you're a raiding mage and perform well, obviously you have no reason to second guess it. But it is not proven fact.
This is what I'm getting at: Everything we do right now is not grounded in fact. "Fact" is a difficult word in a diverse environment like WoW anyway, but back in the day at least we used to have somewhat reliable simulations and calculations to show us why something was working or not working the way it did. These days, we just do it. If I may exagerate a bit here: The mage class right now is like a tribe in the jungle, sacrifing a goat every month to make sure the sun keeps rising every day. And alas, the sun does rise every day. But we don't understand why.
Now, this is not generally a huge problem. But it does become one when you strive to optimize your gameplay. What so very few people have been doing during MoP is QUESTION what we are doing. Test and present new ideas, even if they turn out not to be right. It could very well be that the commonly accepted method of playing is also the optimal one. But we don't have any proof. This is why it is so hard, if not impossible, to reliably compare speccs, or their performance: If we can't even be sure that the current way we play Frost is the right one, how can we be sure that Frost is underperforming?
We need to question the very basics. Look at Frost and the debates about gearing. Look at Arcane and the problems in chosing the right mage armor. Look at countless other small issues that have been brought up but are rarely resolved in a satisfactory manner. Most of these issues have very good "rule of thumb"-style solutions, that allow me to make decissions in a raid on the move. But they are not fact. If we had reliable simulation, we could resolve some of these questions with certainty. But we don't. That is why all of our discussing and arguing and bickering feels so hollow to me: We don't know enough. When you say in your last paragraph that it is pointless to discuss questions of DPS and DPET in different target scenarios, I wonder what else theorycrafting SHOULD be about. This is precisely the stuff we want to figure out and need to figure out. Why else would we come to a forum if we already knew everything?