If you had the power to add one feature no questions asked, what would it be?

[alibutterfly]

People have already thoroughly covered the idea of a functional, searchable, comprehensive glamour log + dye log that unlocks pieces permanently as you acquire them, as well as the idea of upgradeable housing (buy a small, upgrade to a med in the same plot, then later a large, etc.), so I will go back to the dead horse I love to beat...

I would put everything that functions as a currency (its only purpose is to trade it for something else) INTO THE CURRENCY TAB/WALLET, from the moment such items are implemented in the game. I shouldn't have to throw away tokens, totems, doodads, etc. that I've legitimately earned in order to make inventory space, just because "well, you can always run it again though." I shouldn't have to run something again to get another copy of a currency I already legitimately earned.

My entire chocobo saddlebag is full of 8-man raid tokens, and there's literally no reason that should have to be the case just for me to hang onto things that my gameplay has legitimately earned me.

[Limecat]

My entire chocobo saddlebag is full of 8-man raid tokens

I'll tack on to that a bit, and suggest that dated tokens should all be consolidated(i.e. get rid of all the manifestos/whatsits/used gobcondoms/etc from Alexander and replace them with a single Alex currency) the same way tomestones eventually get melted down into poetics.