A few things.
They wouldn't spend this much time on a graphic upgrade if it was in maintenance mode.
FFXI has been out for 10 years longer and it still gets content.

If you don't like the content. Hopefully there is something that can scratch your itch.
As for my hubby and I We played FFXI for years, Then D&D while there was rolling power outages in Japan, Then some Wow which my hubby liked a little and continued to play after I went back to FFXI. When FFXIV came out I switched to it.
A few months later my hubby came on board. When while we waited for 2.x we went back to FFXI. Once 2.0 came out we have tried a handfull of other mmos but keep coming back to FFXIV. My hubby doesn't even like FFXI at all now he says it's to slow, and the graphics don't hold up.

For not FFXIV will be our home and when we take breaks it's mostly to play a signal player game.
I didn't check the OP data center but Crystal is pretty damn full with login queues on most servers every hour of every day. Sure a auto AFK logout would fix this and I don't know why SE doesn't use one on congested servers but ya it's hoping.

Until there are no servers without X's I wouldn't even think servers are slowing down.
https://na.finalfantasyxiv.com/lodestone/worldstatus/