A support tech likely has no control over it, but knology.net belongs to Wide Open West, so all the routing is done internally. So at least you're not being handed off to another provider in the middle. Since NTT is largely just backbone in the USA, it's easy to get a network map of their stuff. Other backbone providers also have them sometimes. (There was this really cool one I had at work for a while, but it was discontinued.)
I can't find a very good network map for WoW, but their business pages had this?
WoW Network Map for Business
If it's the same case for consumer stuff, all the network is basically built out to service a particular set of states, so they're gonna take the shortest (read as: least amount of hops on their own network) to get to the nearest NTT network, which in your case, appears to be the New York location. I have to assume you're likely more geographically located to it than Chicago, which is where the next nearest NTT network would be.
When using WTFast, your connection probably ignores a lot of that and just heads to the nearest "big" backbone provider and gets a nicer route, which is why things like ping, jitter, and packet loss go down.
If you've got local friends who also play FFXIV, see what provider they have and if they have the same connection issues. Compare traceroutes and so on. Unfortunately, it's unlikely that your ISP is gonna build out expensive infrastructure unless they start expanded to additional markets. ...we can't even get the big-name providers to build out better infrastructure in a timely manner.