I decided to give my 2 cents about what I believe would help with the content droughts we have between patches.
This game severely lacks gil sinks. Everything other than the ugly golden mounts (that don't have a lot of appeal as far as I know) is rather easy to buy. It is also easy to sit on a mountain of gil if you're not burning everything on food and potions for savage week 1, which most of the playerbase isn't doing anyway. My personal experience is that while I enjoy crafting, gathering and selling stuff, I have no incentive to do so because I have a steady stream of gil from my FC and have no interest of gaining more gil just for the sake of watching the number go up. I bought everything I wanted for my main and my alts and other than buying furniture for decoration there's nothing left.
I believe this could be fixed with the addition of apartment upgrades(500k->2m->15m->35m for example), adding more craftable glamour per patch(preferably some that can be gathered and crafted from scratch and some using dropped materials from treasure maps and savage raids), silly buyable titles, more dyes, and more tradeable Modern Aesthetics(both facepaint and hairs).
Allowing mogstation items to be bought by gil, preferably costing exorbitant non fixed amounts to avoid gil buying, could also be a good option (this can be done by checking how much the rates for buying currency are and picking a gil cost that would end up as significantly more than straight up buying from Mogstation)
Another related issue is that XIV needs to work harder on bot culling. Bots sink the prices of crafted goods and gathered items, which hurts the gil issue we have today(everything is too cheap) and would make earning the larger amounts of gil needed with the addition of said gil sinks infuriating and frustrating for players.
I understand that this game seems to have a philosophy of not forcing grinds and not making most things too hard to attain, but I believe such changes would bring way more good than harm while using less resources than something like Island Sanctuary.