no, the whole point was to stay in the realm of Adobe tools to evaluate which shot is the best for DNG PE editor... certainly w/ rawdigger I can find out very easy which shot is the most ETTR'd (but then that does not mean that the very most ETTR'd shot is the best one for DNG PE or is it)
Personally, I see no need to restrict oneself to Adobe tools. ACR/LR are for visual editing and rendering of raw files. If one desires quantitative photometric and colorimetric analysis of the raw file, it is often best to look elsewhere. As my previous post demonstrated, the most ETTRed shot is sometimes not the best for the DNG profile editor, since an ETTR shot without clipping in any channel was rejected by the editor with an error message that the yellow patch was overexposed.
and one of rawdigger co-author says that linearity of the camera (not a single sensel responce on die taken w/o consideration of the whole sensor, its toppings and the rest of the signal processing circuitry) is not exactly a given fact within 1/3-1/2 to raw channel clipping, if I am not mistaken, at least not for all cameras (even modern)...
It is often not documented, but I understand that some cameras do some preprocessing to linearize the data from the sensor that is written to the raw file. One must know one's camera. My previous work with the Nikon D3 does demonstrate that the sensor is reasonably linear right up to clipping as shown below. To the extent that the system response is not linear with higher luminance values, it is best to avoid excessive ETTR and work with the linear portion of the response.
it does not really matter which method for as long as an average Joe can stay just within ACR and DNG PE - because that the market where XRite and other vendors are peddling the product... digging for a value of BaselineExposure tag is not nice... Ideally the next version of Adobe's DNG PE shall offer some indication about quality of the source raw file in more certain terms... one can certainly argue that an average Joe can live w/ whatever profile happens, but that's not nice.
If you want quantitative data concerning the contents of the raw file, the BaselineExposure must be taken into account if you are using ACR/LR. It is a pain to look up the baseline exposure, and it is often easier to use Rawdigger, which also avoids nonlinearities introduced by the tone curve. Personally, I do not like the introduction of the BaselineExposure. It does enable one to get consistent results when using multiple cameras that allow differing amounts of highlight headroom, but if one is primarily using one camera it is a pain.
It would be nice to have some indication of the quality of the source raw file, but, as Eric has indicated, a reasonable exposure without clipping is sufficient and I think he has better things to do than work on such an indicator.