If the 560s do as claimed by increasing clarity, more efficient and added bass, why not go with them? I'll be curious to get impressions I still don't think they'll be dethroning the 6. The 6s were a statement piece for Dr Fang. It is not to suggest he's not capable of taking his considerable knowledge and "tweak" the 6. But I don't know that there is sonically anything to do. Physically, build quality, reliability. In fairness to his 6s, no other headphone invites you to consider speaker amps that shows what they can do. There would be far less mention about the QC if they played well with headphone amps.
From an early impression from someone I trust, the 560 doesn't dethrone the HE-6 - although refining the current HE-500 (i.e sounding better). The comfort factor alone is enough for me to buy ASAP.