If Yoshida wants to have content for everyone I would say yea. Relics where the ultimate hardcore goal in the game for almost everyone, incredibly overpowered weapons but with a quest that took month and months to complete with LS support... and years for those attempting to complete one solo.

If Yoshida wants to hold onto some of that hardcore base which made up a large portion of XI, they need to have at least a few major things like this in the game. The casual content will be breezed through by hardcore players, but with things like Relics and some really hard to obtain items you can keep those hardcore players for years even though they finished all the casual content..

Issue is a quest/goal hard enough to keep hardcore around that quest/task would alienate all the casual from ever getting it though... so they have to be willing to release content that only a minor part of the audience will have access to.

Personally I hope they add it, something that truly represents all the work you did in the game. Something that will be good for the life of the game even through multiple expansions and level increases.