The problem is the server only updates your location every 0.3 seconds, so regardless of location you have the potential to occasionally be running at 300ms.

It is getting tiring reading people calling players who get hit by AOE's bads, it's been accepted by SE as being a genuine problem and if you can watch this and feel that this is good game design, please never get into the industry

http://www.youtube.com/watch?v=G5g4TM1fkCg

The difficulty of a fight should be in coordinating your team, reacting to inconsistent mechanics, maximising your output amongst many other things, NOT in praying the datacenter has registered your new location, the competition has this, why should we accept it in FFXIV?