Although FFXIV has one the better default UI customizations in any MMO I've played, it still lacks certain essential options that would make it even better, even nearly perfect, by default! In this post I'm gonna discuss certain UI elements that should, or should not, be in the game, imho:
MP Bar: needs to be separate from HP bars, with an option to hide it, in both the Parameter Bar and the Party List. An option to hide MP bar for jobs who don't use MP should be there, too.
HP Bar: needs to be separate from MP bar, with an option to customize the width/height. If not possible, an option to make the HP bar rectangular should be there. The tech already exists in the Alliance raid's UI. Just add it to the Party list and Parameter Bar's HP, too. Also, it needs an option to show percentage HP instead of full amount, in both Parameter Bar and Party List.
Recast timers (Cooldowns): need a bigger font size, at least, with an option to chose to put in any corner/side or in the center of the spell icon. Or, give us the option to increase the font size, at least.
Flying text: needs a HUD Layout element for itself, so it can be moved around. Also, needs an option to filter out what infos it shows (healing received, procs, debuffs/buff, etc.). Also, need to separate the damage dealt from any event done to you (separate HUD layouts). I don't wanna see damage done by others, on my target, for example, since it's useless infos for me.
Part List: needs various options. Same HP and MP bars customization as mentioned above, and the option to hide the Levels and/or Names, on the party list. Also, the buffs and debuffs on the party list should show the timers on it (idk why it's not there to begin with, tbh) with an option to filter them out (show only debuffs, for example)
Target bar: needs an option to play with the font size of the target name, separately from the target HP bar size. I shouldn't be forced to maximize the HP bar size just to be able to see the name of my target. Same thing for the %HP of the target. An option to show the full/current HP amount of target would be practicle, too.
Focus target: needs an option to hide its cast bar.
Hotbars: needs an option to hide the actual keybinds. Right now, in order to do that, we need to keybind everything in the second row, in the settings (Key setting 2). Just make it a toggleable option, so we can show/hide them on demand, without rebinding everything.
Summoner related option: An option should be added to the game settings to minimize Summoner's primal summons. I know there is a command for that, but the option should exist in the setting, regardless.
Chat: needs an option to lock it in place.
These are my thoughts, so far. I probably forgot about some things or missed some obvious additions that needs to be added, but feel free to add to this in the comments, of course.