I do notice with the JP servers that damage calculations has a noticeable delay 'at times', but most of the time it's pretty instantaneous. You're right though, ping is a poor way to judge latency.
Current: FFXIV | EVE Online (again)
Former: FFXI | The Matrix Online (FOREVER!!!) | STO | SW:TOR | EQ2 | WoW | Florensia | RF Online
FFXI :: Valefor :: Dareknight, Darexius
FFXIV :: Valefor :: Dare Knight
EVE Online :: Dare Knight, Hazel Knight, Rex Knight