After this, my favorite MMO is FFXI, but it's difficult to get more cross-pollination than we already have, since the two games are fundamentally different sorts of experiences.

I still think FFXIV would be better if it eased up just slightly on so-called "instant gratification" and emphasized long-term goals and achievement a bit more, but a lot of the ways to do that don't really fit into a modern theme-park MMO that well, so they'd have to be pretty careful introducing things like this. I'd like to see the Zodiac/Anima questlines expanded in some way or another to include more job-specific gear, sort of like how FFXI introduced ways to upgrade original Artifact and Relic equipment as the years progressed (and the Empyrean equipment too, recently). Raid tiers could probably also stand to be longer (perhaps 9 months instead of 6), so that accomplishments and content in a given tier had a slightly longer "shelf-life."