I think there are 2 ways to look at this. IMO many DACs have a forward and edgy treble response, it seems to be the norm with so many modern digital front ends. Is it Sabre chips or just DS DACs in general. Not wanting to get into any arguments or go too off topic, but a lot of the HP issues can come down to the integrity of the source. The wire with gain statement, it is so wrong IMO. It is a sum of the components that make up the end system. And if there is a general trend of brighter detail freak DACs, then there is a market for a coloured (if you want to call it) HP that makes the best of those sources, tries to fix the digititous of it. Or we hit the pause button after 15 minutes and start surfing Agon for something else (again).
But as you go up the range with DACs this slowly becomes less of an issue IMO, and you can then chase 'wire with gain' type HPs, the noses that reveal more detail. So maybe when we discuss a HP and how it sounds, better or worse in that persons opinion, we also need to take into account the source, it has a huge impact on the HP. After all, we are talking of a speaker millimetres away from the ear, and one that is low mass and not filtered / affected by room acoustics. It has the potential to be a microscope to the source with all it's flaws.
My view on my Stax 009 is it is a microscope to the sound, and without a great amp and great DAC it is not the a great HP. It really does need the source to be well sorted first. Other HPs are much more forgiving IMO, and possibly that is a strength in the LCD2 not a weakness, for the sector it is marketed for?