Another thing people should try is to bypass Nagle's Algorithm
http://en.wikipedia.org/wiki/Nagle's_algorithm - Explanation of what it is and how it effects online gaming.
It does require editing the Registry so use at your own risk. (the steps for it are really easy to do)
Another option may be to enable User Datagram Protocol for FFXIV (I haven't even attempted this yet so not sure how it would works)
http://en.wikipedia.org/wiki/User_Datagram_Protocol
But if you have a low latency/low packet loss connection to any of your local servers I can see how that would be beneficial to waiting on packet verification.