The one thing relics might have over empyrians atm is they might not be limited to lvl 90, I can't see empyrians being able to be upgraded past 90 since abyssea ended and thats where the weapons come from unless further quests come through voidwatch.

End result relics and mythics lvl 99, Empyrians lvl 90, this is speculation though.

This would definatly help with balance issues, and i imagine this is where their going with them with the changes to dynamis, even if theres nothing in the old city and icelands zones allowing you to upgrade relics, they still have plans to change dreamlands along with all the areas associated with mythics.

I imagine we'll get our answers after said content is released along with the lvl cap raise and their probably trying to keep it under wraps. They said theyll fix them so they will it will probably be later then sooner though.