I'd say they still do some things better than many newer headphones.
I'd argue that they still do a
lot of things that are measurably better than
most newer headphones, regardless of price. There aren't a lot of headphones besides the HD6... series with that combination of excellent channel matching, seemingly decent sample variation, very low amount intrinsic resonances / nulls, vanishingly low THD past 200Hz, all the while having a fairly sensible FR curve to start with.
For me that makes them highly PEQable.
Dekoni's pads can solve what I enjoy the least about them, that is that my ear lobes touch the foam above the drivers. They turn their sound for the worse, but at least the Elite Velour pads I'm using don't change any of the attributes above, and since I only use them PEQed...