There is a few minor details i wissssssh they would add:

-Show targets HP
-LS recruitment window, it can be difficult for newer players to get introduced to an LS (especially when everyone in Ul'dah is AFK.) Multiple FFXIV websites where few LSes post. It can be a bit tough if you start with no friends =/
-Simplifying the party search window, its pretty confusing.
-I hate the lag between when I press an attack button and the attack starting. Is there a global cooldown? If so, show it?! Even worse is how long it takes to get all my attack buffs up (Hawk's Eye, Ferocity, Raging Strike..ect.) Instead of every attack buff having its own animation maybe add a little something special when the attack is fired so it doesn't take 5 to 7 seconds to get 3 buffs up
-An archer is supposed to be mid to long range and takes advantage of the high ground right? Why is my max distance so close (15 maybe 20 yards) and why can I not shoot anything a mild distance below, not even 5- 10 yards.
-Add LOS, my R21 Arc, at the time, was running through South Thanalan when i was hit for 3150 by a R75 puroboros who was apparently in the cave below me -_-. This should not happen.
-Stacking of action bars (Switching pages all the time is saddening)
-Why not make it to where we scale our own UI. Everyone likes their Ui set up differently, so why not have this option?
-When my character is running, if I draw my bow or any other weapon my character slides 5 to 10 feet, and then starts running after its drawn. It was the same in FFXI why can this not be fixed?
-The camera bouncing when running down stairs or a ramp!
-Make it so the NPC's can repair my equipment no matter what.. I don't have enough time to level every profession to repair all my equipment.
-Add local time to the the widget with Erozea time please!
-Add a board to pick up leves from another city.
-Add all quests to the map so they can be seen when they are available.
-Menus and sub-menus! Why do i have have to click a button to bring up a sub-menu to click to the button to bring up the box to accept a resurrection/party invite? Same with Aetheryte crystals and ect It's madness I tell you!
- I hope they haven't taken jump off of their to do list.
-One aspect i really do not understand is why the map is so limited and why it still has to be sectioned off.. In most all other MMORPGs this is not the case ( I can't actually think of one that is besides FFXI.) Eorzea has all this pretty landscape and yet you cannot even get to half of it.. Jumping would definitely help but why can't i fall off of things? For them to try and make it more realistic with the movements and everything, why is this impossible? I myself really do not need this safety net, if I fall off of something its my fault. I really think SE is limiting themselves with this type of map, it takes away from other things that could be implemented later like flying mounts or anything else that would allow you move through the air instead of on the ground.
-I miss the action you used to have riding the boat on FFXI! Nothing like getting your little noob butt kicked by the Krakken!


I'm sure there is more but these are some of the worst annoyances off the top of my head. On the positive side I'm loving all the new content they are adding to this giant void (aka FFXIV.) Keep up the good work!