You don't seem to have a feedback/suggestions forum? So I'm just going to put this in GD.
I have been around the block a few times in MMO terms, I didn't actually start until a friend cajoled me into playing EQ2 just after it released. Since then I've played most of the triple A MMOs that have been released, I never played FFXI. I bought the game at release, having played in the beta as I had not been playing MMOs for a while, and just wanted something to play. I played for a while, I appreciated some of the things the devs put in such as the class system and crafting, but ultimately I was driven away by a combination of boredom in grinding, the frustrating UI and the complete lack of short term goals. I continued following the games progress, always read the patch notes and just recently decided to come back and see how things have changed, here are some of my thoughts after a few more hours playing around in Eorzea.
Engine/UI
The first thing I noticed upon logging in was the massive performance gain, I've gained anywhere between 10-20fps depending on situation and that is on a higher graphics setting than I was using previously, so kudos there, the game looks fantastic and runs very well despite this. I've still got two major gripes though, firstly:
Why can I still not ALT + TAB? My guess is it's an engine limitation as a result of building a console engine then trying to get it to work on PCs, but it's ridiculous, I've never seen a thing like it and you really need to do your best to get this sorted. I can't speak for everyone but I sure I am not alone in browsing forums e.t.c. whilst I do things in an MMO, having to sit down and do nothing but play because I cannot alt tab makes it feel like much more of a chore at times.
Much more of a minor point but moving all of the settings from the config file ingame at some point would also be good, just because getting into the game is a lengthy process, and it's a real pain in the ass trying to optimize your FPS when it takes ~2mins to get in game and see what effect your changes have had.
I have no real issues with the UI design, now it is more responsive I can't really fault it since you can hotkey all the windows anyway. I do think a few window redesigns are needed here and there but they are not key issues. You're still not providing anywhere near enough information to the user, and it isn't like you can Alt Tab to find out...
I was going to categorize further but didn't really know how to, so I'll just keep musing...
Coming back, I was impressed with the responsiveness of combat, plus a few neat touches like ranks for creatures in the world, the sort of handy little change that really help make the game more relaxing to play.
I've done a couple of your quests and they are pretty standard stuff, hampered somewhat by the dodgy UI implementation, it's too hard to find out what you are meant to be doing, and there is absolutely no guidance in the few I did, so it was a case of run towards the dot on the map, hardly final fantasy...
I think the game is missing a story, I thought there was meant to be one? Perhaps I just havn't found it but I think you need to go back to this and really build it out, make it so that at every level you have a choice between progressing the story or doing side activities like quests/leves e.t.c. Because right now frankly it just feels like a massive grind to reach max level. (Of course right now there is still NOTHING to do at End Game, but I wont comment on that as I'm sure it's coming).
You need to work in some sort of alternate advancement, something like a faction system with the cities, to give an extra meaning to the things you are grinding.
Socially you've got a lot of work to do, as far as I'm concerned the entire social structure needs a complete rework from the ground up, scrap linkshells, or turn them into more of a standard MMO guild, without a size limit and developed in the sort of way that they have been recently with levels e.t.c. a guild hall style area would be good I'm sure. Give us standard chat channels, NO ONE talks in the game and it feels like you are running around in a morgue at times.
Keep working at the game, you are getting there, the foundation is more solid but you need to keep expanding it, some new classes, particularly some fluffy entertainment style classes would be warmly received. Keep adding quests as well and I'm sure the game will grow.