you speak of recordings that date back to when?

At least from the 80s to present. I remember going to Tower Records as a kid and bringing home around 20 classical albums only to find maybe one or two sounded decent. My favorite form of classical butchery is the foggy monolithic string section that sounds like one person playing under a pillow. I had to join the Time Life collection back then to get half decent sounding classical. I have very good quality classical now, but it's still only a small fraction next to the ocean of garbage out there. Acoustic and Jazz has a higher ratio of quality recording and mastering than classical IME.

Quick note: dynamics in stats are mainly limited by the amp, to get a relatively insensitive 007 up to 120db peaks you need a truly beastly amp with a high slew rate, else you'll have a slow dynamically compressed sound with large portions of the frequency response sagging. Maths @ http://www.tubecad.com/november99/page3.html http://www.head-case.org/forums/topic/12155-output-stage-current-requirements-for-electrostatic-headphone-amps/

Yup. 

Quick note: dynamics in stats are mainly limited by the amp, to get a relatively insensitive 007 up to 120db peaks you need a truly beastly amp with a high slew rate, else you'll have a slow dynamically compressed sound with large portions of the frequency response sagging. Maths @ http://www.tubecad.com/november99/page3.html http://www.head-case.org/forums/topic/12155-output-stage-current-requirements-for-electrostatic-headphone-amps/

Eh, the way I read that, even the old SR-X amplifier would do just fine as long as its supported by a constant current source.

Do people agree with what I said earlier about perceived 'macrodynamics' correlating more with 'impact' than with SPL?

Probably it is. However, what is that "impact" physically? I suppose that's good impulse responce AND good bass performance (flat square wave). Drum stick strike produces quite wide frequency spectrum.

Then, perhaps, the lack of impact in planars could be attributed to high-frequency combing due to large driver size. Modding Hifiman owners could test that by "ringifying" their drivers perhaps - covering the centers of their drivers with some impermeable material, preferrably covered with something sound-absorbing. Perhaps, even permeable, but absorbing higher frequencies. Covering 1/2 to 2/3 of the whole driver area should probably be enough - that'd already reduce combing a lot. Other drivers doesn't seem to be as fit for that.

Though, planars typically have quite good impulse responce by eye, so it's most likely something else.

According to this: https://docs.google.com/presentation/d/1wi8M-HSeK0JF33P-5ypydQjQ4OshRQhvWM0IX2h0NQ8/edit?pli=1#slide=id.g25f83b2cd_0456, planar magnetics can't do treble above 10khz very well, which might be a part of it.

It doesn't say that orthos in general can't do treble, it says most of them aren't good at it. Looks like most really high-end orthos have at least good enough treble. Fostex RP has very thick and stiff untensioned diaphragm that's just clamped. No wonder it's not good at treble. Plus the driver's 'cavernous' construction. Has anyone tried filling the metal plates with some material so diaphragm would face a flat surface with holes instead of peaks-and-volleys of magnets and plates?
Though HE-400 has apparently somewhat similar magnet system yet treble isn't that bad.