If you design anything and make small steps of variations along the process, you will have to keep some factors the same or you have no clue which of the variations has contributed to the change you perceive. If you design a headphone at some point you will have to make a decision to choose a certain DAC and a certain amp topology and stick with. Then the headphone will be fine tuned to sound the ultimate best with this combination. Consequently a change to a different DAC or amp will produce a different sound than the developers have been aiming for.
Perfect example is the much discussed HD800. IMHO these phone are dead honest. They tell it like is on the recording. Combining them with a bright DAC or amp will produce a bright sound, that's not the fault of the phones though and they are not "picky". They just let you know when something in the set up is out of whack. Acc. to the developer of the exasound DACs, these were developed using the HD800 as listening tool. In my set up the HD800 sounds as close to perfect, as I can imagine and I compare to live acoustic music. Any other headphone can possibly inch still a little bit forward in certain areas but to expect a SQ jump even by investing $55k's is delusional.
Coming to the Orpheus II finally, I completely understand that Sennheiser wants to control how these headphones are listened to. Combining them with a unsuitable amp or DAC will get weak bass or overly bright highs etc and the blame will come down on the headphone. Nobody blames a speaker for the bad sound when it's combined to an unsuitable amp. It's pretty obvious that the set up needs to match in order to play at the best possible level. The more accurate a transducer is working, the more obvious it will be when the pairing is not a good match. The HD800 is already at that level and most likely the Orpheus II is pushing the limits even further in this respect. Given the unique in cup amping approach in the HE1060, it is quite unlikely that there will be other amps available to drive these unique phones any time soon.