Uhm.. related:
What about a separate, dark-mode, importing paradigm?
The Dark Sets (like my beloved kingslayer set) of tw2 were absolutely amazing!
Give to the player the ability to import them as "starter-sets" for the tw3 dark-mode, could be something terribly intriguing.
Also, having the "Dancer", "Addan Deith", the "Forgotten Vran Sword", the "Deithwen", the "Caerme" the "Mourner" or the amazing "Zerrikanterment"..
could be very cool: I dont care if the will have a 5-10 + 2% something once imported at the start of the game..
But i must say that also having them like craftable objects for later or end-game experiences (along with the new weapons and with the appropriate level/requirements, in order to respect their legendary halo of their associated myths
) could be absolutely amazing.
For example, this could be a nice way to have the Aerondight or the D'yabel in the tw3.. maybe also with some end-game tw1 related quest (just an idea)..
Swords and armors, in the Witcher, are so good that they deserve a separate "lore" and "storytelling mechanism", imho. XD