Yes, we always need more glamours, the more diverse the appearance of players the better. And you don't seem to understand the idea of crossovers, you want to generate interest in both things that are currently active. We get earlier FF reference in other ways like Veteran Rewards.
have you seen the ironworks gear? there are very few limits to what fits with Garlean tech/design. also the Void Ark? we can uncover lots of fashion styles from the previous eras.
And I don't personally care about Deus Ex but I don't see a strong argument against it if that's something they want to do.