Just a though: bad netcode might not be the origin of packet loss or latency, but it makes a game unplayable with those (common) occurrences.

FFXIV's battles are designed as if it was a solo/LAN game. It doesn't leave any room for the slightest lag/latency/whatever network fluctuation we all get at some point or another.
Buddy, I'm sorry, but you don't know what you're talking about. "bad netcode" is not the problem here. That's what everyone immediately thinks whenever they see that they lag in one game and not another, "oh, it must be bad netcode." But no, there are a million possible reasons for network issues, and we know exactly what the issue is. Certain major backbone routers on the path many connections take to reach the NA datacenter are expereincing difficulties. This isn't a netcode issue, it is an internet issue.