Ok, testing time. Just for amusement, I applied the curves from that list to the Audeze LCD2C and Focal Clear, which I own. And OMG NO. What the hell is this? I don't know if the measurements are wrong or this Harman curve is even less ideal than I suspected, but those curves sound awful. They are light years apart from the curves I made on my own for this headphones, even completely the opposite in some cases.
In the LCD2C they decided to put a whopping 10 DB increase at 4060hz! Of course, this is unlistenable and sounds insanely harsh at any volume other than very very low. I actually bought the lcd2c because of their very relaxed and warm sound, and at most I put a general +0.5db upward tilt to bring back some presence. This intense boost in mid treble is totally unjustifiable. The Bass rise is actually similar to what I use (they put +5 db low shelf at 110hz, I use +4 db at 130hz), and the overall curve lowers the very irritating mids that I find to be too boxy, so I also apply a reduction there. But the overall sound signature with their curve is hollow and extremely harsh.
As for the Clear, it's tamer, but still wrong for my ears. They for some reason put a -4db reduction at 200hz, a region I usually boost up because those headphones just lack in the bass guitar region. It gives a really anemic presentation. They also seem to think this headphone doesn't have enough treble energy because they put some boosts there, which makes it even more piercing than usual. I do agree on the general reduction in energy around 3500hz that I also apply myself, but they boost it back up at 4300hz which defeats the purpose. Again, this sounds to me a bit hollow and quite harsh.
Finally, I tried putting on pink noise and listening through the suggested curve of each headphone, to see if it actually results in a similar tonal balance. It's not, and I could even dare to say they sound more dissimilar with the curves then without them.
So my conclusion is that based on this very rough experiment, the Harman curve is just probably not for me. I could see how it would be appealing for short term listening because of its emphasis on presence and impactful lower bass, but for long term it seems to me extremely fatiguing and lacking in warmth.
On the other hand, this is the same sound signature I heard in numerous high-end headphones (maybe with tamer bass though), that I generally despise. So maybe there is a large percentage of the population that do appreciate this sound. Well good for them, I say. But I still don't think every manufacturer should aim for the same response. Otherwise where is the diversity and opportunity for surprise?