personally I would rather a combo of ARR and Heavensward for Relic grind. It encourages players grinding out the Relic to do older content which helps new players. Eureka dosn't...and once Stormblood is past no one will do Eureka its like diadem there is zero need to go in. The biggest nwgative effect I have seen is people not having an insentive to do early stormblood content like omegascape. my friend just reach 70 so we taught we get him some gear on omega scape normal and then unlock stigmascape....no one was doing it an hour wait for omegascape 1..... least with arr and hw relic people did older content for the grind....