All relic pieces with unique effects are still useful, because none (or almost none) of those effects are duplicated on the empyrean. Especially for me on DNC, the relic body makes violent flourish actually work. No part of the empyrean enhances violent flourish, so I still need the relic body.

And not all relic gear was anywhere close to best in the game. DRK's was mostly terrible- macro peices for nuking or certain abilities, and nothing more. For many jobs, only one or two pieces were any good.