You drew a conclusion that the Exposure slider works in a linear fashion. You based that on an example of an experiment you performed with a test chart. Fine as far as it goes, but the example I gave was intended to suggest that maybe it is less linear than suggested when called upon for other purposes. Perhaps someone who really KNOWS the answer to this could clarify it.
From its description in the Adobe help, the Exposure slider should perform a linear scaling of the luminance data, just as decreasing the exposure by 1.0 EV scales all the picture elements by a factor of 0.5.
This can be shown by experiment with Imatest and a Stouffer wedge. With the ACR defaults, the black point is 5, which rolls off the shadows. The default Contrast of +25, Brightness of +50, and the default point curve are applied with the exposure adjustment and complicate the resulting curve.
Here are the tone curves with ACR defaults and Exposure set to 0 and -1:
Here are the tone curves with ACR defaults except for Black = 0:
And finally, here are the tone curves with ACR linear settings (black = 0, contrast = 0, brightness = 0, point curve = linear):
This last set of curves demonstrates that the Exposure adjustment is indeed linear over the entire range, except for the deepest shadows where the data are not good.
Panopeeper knows quite a bit in this area and also believes the Exposure adjustment is linear. Anyone who states otherwise should back up his statement with data.
The so-called EV compensation of ACR (it is a misnomer) is a linear operation, at least that is my observation. The "brightness" adjustment is non-linear.
Regardless of who advises what, let us just explore the logic here, and as I keep saying, what's optimal will vary from one image to anther, albeit there are general principles guiding the workflow. So let's say we start with an image which has blown highlights and is otherwise under-exposed. Where would you start? Would you ramp-up the Exposure slider blowing the highlights further, or would you Recover the highlights and then ramp up the Exposure, working inter-actively between them till you reach a limit or a visually satifactory result? Not being dogmatic, I would say it doesn't matter much. In this kind of situation, it's just a matter of workflow convenience because ACR will process all the moves in its own determined sequence regardless of when you or I adjust what. For an image of this kind, I like playing with Recovery first, just to see how much this targeted adjustment can do for me, and to see how much head-room it gives me for then correcting the under-exposure in the rest of the image. But I could have started with Exposure and then applied more Recovery.
I think Thomas Knoll's suggestions are for routine images in general, but there is no one more qualified to give such advise. I agree that one must evaluate the individual image. The example you gave with a generally underexposed image with blown highlights represents a high contrast scene whose dynamic range is greater than that of the camera. One must decide which luminances to favor in the final image. As you note, the order in which you do the recovery and exposure adjustments does not matter, since all these adjustments are concatenated and performed in the preferred order by ACR. As Schewe demonstrates in the tutorial, a curve applied to the highlights can also be useful and can give more control than the sliders.