Sorry, that was a typo - should have read "all the
bad parts". There are new pads, but I don't know if they fix that dip. Pretty much every LCD I've seen since Fazors started has it (even the ones without Fazors), until the LCD-5.
I don't know if anyone remembers or has seen this, but there was great controversy on Innerfidelity when the LCD-4 and Utopia both came out. Tyll skewered the LCD-4 for the treble quirks described above (to which Audeze made several official responses), and Focal sent him a rigged Utopia which was just about the best headphone ever made but not representative of any other unit ever (whether this was deliberate or not is unknown).
Once the dust settled on that, he brought in Bob Katz to check out those headphones. He took an intense liking to the LCD-4, comparing it to a six-figure treated-room speaker setup. He said the speakers were better, but the LCD-4 wasn't even
that far off and the fact that you could even compare them was amazing in his mind. He then brought in a team of audio engineers under his tutelage to compare the two headphones, with all of them preferring the LCD-4 in pretty much every way.
https://www.stereophile.com/content/katz’s-corner-episode-13-big-shootout-audeze-lcd-4-vs-focal-utopia
https://www.stereophile.com/content/katz’s-corner-episode-14-guest-listeners-shoot-out-audeze-lcd-4-vs-focal-utopia
I cannot deny the tonal quirks you indicated, and was in your seat saying I was giving up on those headphones. But something pulled me back, and I haven't regretted it yet.
I did own a pair of LCD-XCs and LCD-4s at the same time, and apples to apples, I felt that the LCD-4 was a
better value at both new and used price points than the LCD-XC. I get why the LCD-4 was $4k, and feel was over twice the headphone as the LCD-XC at $1800. Used, the LCD-4 had more going for it at $2k than the LCD-XC did at $800.