I used to play on NA servers back when EU data centers were still located in Canada and had ping around 200. Also have an alt on JP DC with around same ping. My normal ping on EU is from 70 to 110, which is okay.

From experience I would say that FF14 is somewhat friendly as long as your ping is below 300, but at that point it's already on the verge of being uncomfortable for some instances where very fast reaction is required. 1000ms sounds like a nightmare for high-end content. If you aren't planning to do Savages and Ultimates it still can be playable, but I suspect that your healers might cry in the process.