Throughout my time as an audiophile I've read quite a lot of positive reviews regarding the DT880 Pro, especially the 600 ohms version, I've seen it being highly praised for it's build quality, comfort and sound, however there is one fault I'd point out: no removable cables.
As much as the DT880 Pro is marketed towards professional usage ( at least that's what I think, given the "Pro" in it's name ) it is adored by the audiophile community, thus I'd love to see a more audio-enthusiast focused version which only difference would be having a removable cable with a 3.5mm connector on each cup. I reckon the benefits would be quite sizeable : you wouldn't be confined to the 3m cable of the original version; it'd possible to run it balanced (which would help with the endeavour of properly amplifying the 600 ohms version); should the cable fail due to an accident or the throes of time dealing with it would be much simpler and , finally, if you are part of Team After_Market_Cables_Ain't_No_Snake_Oil there is an obvious added advantage to such a product.
People seem to love the original's sound well enough so I personally see no reason to alter it. There would be an opportunity, however, in the aesthetic department, a midnight blue/black colour scheme à la HD6XX or something of the kind might be interesting eh ?
To sum it up, my opinion is that Beyerdynamics has wasted the opportunity to make such a product for far too long and that Drop might as well take it upon themselves to bring this enthusiast-oriented headphone into existence ! Since that's already what they do isn't it ?