When falling in Final Fantasy 14, I get damage based on the height.
I fall a lot (mostly on purpose, love to see the Chocobo fly! ;)) and so far died from falling only once, and can't reproduce it.
Even falling from very high places (with or without Chocobo) leaves me alive, with 1 HP.
I don't remember where I fell and died (just that it was not on purpose, I actually fell), it was when I was around level 10. Maybe with low HP falling can kill you?