Hmm, my suspicion was that this was the case. You may be interested in reading this tumblr post, which is about a certain thing that was made to counteract this problem of server validation and ping tax, but for a different MMO.
I fall into the category that FFXIV is clunky and slow. I'm used to being able to rapidly cast skills one after another and being able to animation cancel a lot of my skills, so it just feels somewhat slow to me. Like if I don't have any oGCDs to cast, I'm literally sitting there either waiting for the GCD to reach under a quarter of its duration, or I'm spamming the skill (if I don't want to look at my hotbar). From what I understand, WoW has a much shorter GCD (1-1.5s).