Pfft, you guys can't complain about cash shop, you guys opened pandoras box. (anyone remember Fantasia or riot)
OP:
How about Buying different HUD options (like skins for your HUD.)
Also a very bad idea, for most, but would make a lot of cash: Front of the duty finder line tokens (use one and your automatically placed in front of the line for DF).
How about, In game parser dummy, for lets say 100 dollars.
Next, Special retainer potions, that change your retainer into any of the Scions or other popular characters from other Final Fantasies. (prolly like 50 dollars)
What about a Gambling table, where you can play a gambling game against other players for real gil that you bet. Can sell different games in different packages.
How about drunken emotes for 18+
Lets say Classic Gears from all other FF games
And next A gardener person, who you give seeds to and he takes care of the garden.
I say everything should just cost way more, then people would be happier.