As per this discussion thread on JP fourm:
http://forum.square-enix.com/ffxiv/t...の詳細を明かしても良いのでは
Tahnks to effort of two Japanese players Aji and Emayon:
They are able to find out the relationship between distance and range attack potency as per following screenshot:
At 15M, 100% damage
At 10M or 17M, 80% damage
At 7M or 20M, 50% damage.
Anything at 3M (meele range) and max 25M it is 40% dammage.
The follow screenshot is providing a guide on how to differtiate your range attack potency by looking at color of TP on your action:
Target is near 12M, the color of tp on your action will be in blue color.
Target is about 15M away from you, the color of tp on your action will be in red color.
It seems the effective attack distance for Archery is too short and caused lack of sustain pressure on the healers or casters.