What I wouldn't mind them doing, and I'm not sure if they wanna go this route because of previous use, is the idea behind splitting your weapon in two or four directions:

Similar to FFXI, where you could get a weapon and upgrade it four times to it's master level, this one would be the first level of Curtana Zenith, and then you choose which path you want to go: More offensive, or more defensive. You then do a questline to unlock it, and you keep going down that path, always splitting your weapon into two paths and adding bonuses depending on what you want, or, latent abilities.

This would always grant us a way to improve on the relic weapon and give it a randomness and a unique property. Yes, there are some that will min/max but it'd be neat to have different properties.