Regarding "temporal blurring" and the need for a faster impulse response:
Here is the fastest impulse response of a real acoustical event (not an electrical pulse signal) I've ever seen recorded. It's an electrical spark discharge. Note that each sample period (dot) is 10 micro-seconds, so whole first complete peak-to-trough cycle is about 70 micro-seconds. Recorded at 24/96khz, 5 cm distance.
That's really fast!
What kind of filter / impulse response combo gets close to that?
Wow, that looks awesome! Now what kind of filter gives me that?
Hurm...well that doesn't look like much of a filter at all...what does that do to the sound?
GAH! That's horrible, and very very audible.
So clearly Meridian isn't takings things to that extreme. So what might they do instead?
Well, they could use a filter that looks like this...
Not bad, about -4 db down at 20khz. Which looks like this in the audio band:
Not bad at all. With some noise-shaped dithering you mash down those peaks at the expense of a higher noise floor, but still keep it all well below the audible range. And you get an impulse response that looks like this:
Pretty good, practically no pre- or post-ringing. Where can you get this awesomeness? Well, it's one of the standard filters built into ProTools, the most popular DAW software, probably used to mix and master most of the music you listen to.
Which brings up the key point:
Whatever MQA is trying to do on the playback end, everything else in the production chain impacts the lowest common denominator. Even if MQA has impulse response as good as the ProTools example above, it doesn't really matter if the microphone, ADC, the mixing software, the DAC, and the speakers/headphones aren't equally good.
Combine that with:
1. Reduced compressibility due to noise generation / ultrasonic reproduction in the least 8 bits.
2. Unusual synthetic reproduction of the top octaves
3. A format that requires MQA-compatible playback HW/SW to reach maximum potential
4. A hybrid of lossless and lossy approaches
5. Possibly DRM-equipped
6. No smaller for streaming 16bit lossless
....this all seems like, at best, a lot of work for little gain. And at worst a giant vendor lock-in scheme for a technology format that is likely to never really take off on a wide scale (see HDCD, SACD, etc.).