Regarding the Vana'diel / Hydaelyn comparison, I don't actually think there's any sense in that. Vana'diel is a world created (accidentally) by a grieving goddess as she split a crystal, a "mistake world" as it were, which wasn't as amazing as what it was formed of; but still pretty cool. Vana'diel is connected to Al'taieu / Dynamis / Valhalla / the astral plane and Abyssea via links to other worlds, which Hydaelyn isn't. These links wouldn't just disappear. Furthermore, The 5 races argument's kinda invalid considering Hydaelyn doesn't have Zilart or Kuluu - and the devs have gave out lore about these races which conflict with XI's lore - proving that they're merely similar to XI's races because XI's races were really popular.

Also, none of the Terrestrial Avatars which are charged with keeping Vana'diel are featured in Hydaelyn - aside from Carbuncle. Considering Carbuncle's merely an mathematical arrangement of Aether to a given form in XIV; it's certainly not the omnipotent being Carbuncle is in FFXI. Regarding the thread's original point, there's nothing at all wrong with XI references. There's enough reference to other games within the series (Lightning for one, and did anyone see the Warrior of Light armor in the last live producer letter? I'm crossing my fingers based on pure fangirlism that he's in a FATE at some point.) and XI shouldn't be excluded from that. Especially given it was the start of SE's MMOs based on the FF series, and indeed, very successful.

tl;dr- dumb GD is dumb