i don't support make relic weapons the best again, and more now that dynamis is going to be modified, who knows if they will be accesible for everyone in a near future.
Imo, a good solution would be to make relic and empyrean ws accesible with any weapons (like mythic ws are) with any trial or something, and just make relic's, empyrean's and mythic's aftermaths work with any ws, just for having the weapon equiped, make the weapons be unique just by their aftermaths, in a way that all 3 do the same amount of damage in comparation with the others but they give a unique buff that makes them usefull dependig on the situation.
That way if they were supposed to be the legendary weapons, they will still be, but that doesn't mean that they should be better than other legendary weapons and if you really like a job you will work to have all 3 and use one or another depending on the situation.