It's possible, certainly, but it's also possible the new player hub will be located in an area easily accessible by players that are not yet level 60. If Rhalgr's Reach is located one zone over from the Black Shroud, for instance (just going off the stylized map of Eorzea), like how Ishgard bordered Coerthas Central Highlands, they can have the Job Quest givers in the new main hub while also not gating them behind content.