If you could add 1 thing?

Blue Mage.

I am DYING to play Blue Mage again. I need it.

Vanity slots, I hate finally getting a nice looking set only to replace it with the same potato sack looking robe like 3 levels later D:

And a barber shop, I like customizing my character lol.

the ability to hide all the other players that are not in my party

an easier way to blacklist spammers

a Two handed sword class!!!! and a twin dagger...

I'd like the ability to dye ALL armor. Being unable to dye unique armor is relatively disappointing. Tell me it wouldn't be awesome to be a Lancer in Red or Green armor instead of just dark purple. Or a Scholar in White Battlemage gear.

Clickable aetheryte hubs, or at least names when you hover over them. Or, the ability to travel to any aetheryte crystal within that city from the main city crystal, rather than having to run to the closest little one. Small things, but it'd be nice.

Oh, and the ability to see current gear compared to the gear you're hovering over. Sometimes (okay, most times), I care more about defense/magic defense when selecting new gear swaps. ESPECIALLY when on a crafting/gathering class.

Dancer tank. We need more tanks and healers.

or a new beast race like Bangaa's, I would love to play something with scales.

"instant" abilities to apply their damage/heal/whatever instantly, and not be delayed by animations

Dress-spheres from FFX-2. Yes, i'm serious.