The formula: every patch and every dungeon is just a copy of the others with just a change of scenery and mechanics. Nothings new or different and makes the game predictable. There's no real evolution.
Item Bloat: "Oh hey! A thing of vermicelli! Is this worth anything, make anything good or worth keeping? Heck if I know! /vendor" Far too many that range from nearly useless to highly valuable. Hardcore crafters I know have to keep spreadsheets on hand to keep track of drops and what makes what. Coupled with the whole normal quality and high quality thing. So double the everything and double the inventory management and sorting frustrations.
Menu Hell: It feels like even the simplest things take longer then they should due to how un-streamlined the menu systems are and how bulky and cumbersome they are. Like not to long ago I upgraded mining gear and unmelding my older gear and converting it all felt like it took a century. Select each piece, open menu, click unmeld, select materia, click accept, wait for the unmelding animation, repeat a bazillion times. By the time I was done I didn't want to even play anymore for the time.
Focus on aesthetics over content: "Well, we may not see more then two new dungeons each patch, but golly at least now I don't have to worry about having to resit down on a bench after one is done! I sure don't wanna miss the show of the four bards in front of me trying to out perform each other badly!"
*EDIT*
I forgot one thing
Bland gear progression/Unmotivated gear progression: It's really hard to get excited for new gear and things when all it is really is just a small bump in item level and nothing more. I don't remember ever really being excited for an upgrade. With that comes the unmotivated part of things. I went through the nightmare that was making a relic weapon in 2.0...which was fastly replaced through the start of 3.0. It's just become increasingly harder to find the will and urge to push for these things when in the back of my mind is saying "just wait another patch, the same item level thing will nearly be free and won't take months of tearing my hair out to get"