from my perspective, PvP in this game lacks alot of things, it clearly doesn't feel fleshed out at all and it also isn't rewarding enough on the long run.

-Gameplay has a too strong rock-paper-scissors feel to it imo, every role only does what it is suppoest to do and nothing else, there is almost no room for creativity aside for selecting 2 bonus skills. I mean, you can get lucky as a tank or healer if you find that one unlucky fellow with low HP who just happens to have his unlimited supply of potions on cooldown but aside from what? theyre both just there for stalling time and a huge invisible "please hit me, i cant fight back!" sign above their head (tanks have it a bit easier since they can abuse the laws of gravity and knock one guy off the ledge every minute).
almost every other MMO out there (and those in the past) usually solved such issues by having either tech trees or a skillkit that can respond to any situation but with different magnitudes depending on the class/job you played.

and by the topic of Potions, throw those things into the Trashcan where they belong to. If you think that "i will just melt without these before i can do anything" you should rethink a few things. playing recklessly can and SHOULD punish players who get ahead of themselves and overstep their boundaries and limits. Those Potions only stall needlessly for time and drag fights for way longer than they should, it would be more convenient to fix such a thing with potency adjustments on skills and abilities.

-Feast would be more fun if it would have more variety, like having no limitations how the party is formed. is it unbalanced? probably, but keep in kind that "balance isnt fun". is it dumb? definitely but it will also be fun. it would also be great if the party sizes had also more variety, such as 2vs2 and 3vs3 matches.

-Duels are as good as nonexistent and with a good reason (see gameplay). it would be really great if duels were also avaiable on more areas rather than just inside wolves den pier (maybe even allow it inside large houses or on the garden). Other MMO's usually have the option to duel someone almost anywhere possible, so why not impliment something similar as long as it isnt inside the city.

those are just a few idea's which most likely have been probably mentioned countless times already by other players and i am absolutely certain that this message gets ignored anyway aside from a few players, but i do wish that PvP would have a greater spot in FFXIV since it is clearly lacking in alot of things.