Currently, the North American servers are located in California. It might be the most populated state in the USA but about 80% of the country lives in the eastern half. And of course there's a noticeable amount of ping over this distance. In addition, when there's a node having issues near the FFXIV servers it means a significant amount of the playerbase is going to be affected. Many people affected by this end up paying for a service to reroute traffic on top of the FFXIV subscription. Many of us had a blast in November 2023 during the cloud test from experiencing normal latency after going through those issues for years. As someone whose ping can vary from 70ms to 100ms (120ms lately) I didn't even know that the game could feel so good at 20-40ms. It's a completely different, better, and snappier game.
Anyway to bring this back to data center populations, Square Enix just needs to move each DC to a different location. They could keep one server in California, move one to the central United States (perhaps Texas), place one in the Canadian data center where the cloud test took place, and move the last one to the south eastern United States. I guarantee that if Dynamis was in Atlanta so many players in the region would swap to it that you would think it was around for as long as Aether or Primal, even if the transfer wasn't free. Are you having issues with a node again? Now instead of paying for a VPN you can DC travel to the second closest data center in a different physical location until the problem ends. Is half your static split between east and west? Don't worry, you can still meet in the middle with the central US DC while spending the rest of your time at home.
This post is pretty US-centric but it would also improve the experience of the Brazilian playerbase and the data centers in EU and JP could probably do something similar to better serve players in those regions.