The straight answer and the one least likely to be well recieved is that you get what you get now.
The current situation FFXIV is in both developmentally and fundamentally is what you get, however SE handles the money coming in from the game is up to them and sadly it doesn't seem like they want to pump funding into FFXIV to really improve it from the current standard. I know the devs always talk about hiring new people and increasing their staff and blah blah blah, so presumably at least some fair portion of the funds are coming back into the game we pay for but the real question is how much? Presumably the cash shop funds go to the developers without being touched, monthly funding I have no goddamn clue because they're raking in the money (depending on how many players have the Legacy sub cost of $9.99 anyways) so I can't imagine SE is literally taking all of it.
Which leaves the biggest question of where the money DOES go and why?
Though I think an equally important question would be: 'How much worse could it be?'
Without the cash shop they're losing a pretty nice portion of funding and that loss of cashflow will directly relate to the game and what they deliver on, especially if they have a mogstation team like other games do that specifically works on shit to be sold. GW2 has one, WoW has one, SWTOR has one, TERA has one, so it's a fair bet that they do too which means there wouldn't be any of the cash shop goodies at all without the dedicated team working on them so right there you'd just have less stuff in the game overall. Now presumably the shop doesn't just fund the team cranking out mounts and skins so the primary team working on the game itself would lose out on some staff and with less staff working on it I can only imagine the quality and breadth of content would reduce. Further there are players that only play to look pretty and have big shiny mounts so you risk losing those players too and that's not great, no whaling and no whaling accounts would be a solid detriment depending on what those crazy players are dishing out since FFXIV has one of the least impactful cash shops.
So yeah, you get what you pay for and you get to enjoy the fruits of other peoples' labor when they spend extra cash on the game.
Win win.