By far the most damaging thing to FFXIV is this. Duty Finder makes the game feel like it's an instance-only game and not about people you can build long-lasting relationships with.

My wish is that they would an option to search in your server only so that the people you meet in Duty Finder you can keep in touch with and run future dungeons with.
There also needs to be a better goal-system which pits certain affiliations (Limsa affiliation, Uldah affiliation, guild affiliation) into partying up together.

The game has a bit too much freedom. A few restrictions to socialize would do wonders.
By far DF is what brings the game down the most. The game honestly already has millions of people already.