Spoiler
I do not play a lot of shooter but I think I can at least say why thrown 81 + do not use the skill Hawk Eye. It rises 712 full on attack ability and rate .. I believe it's 50% hit to avoid the miss of skill X to use 16 skill points in another skill that can be of greater importance at the time of pvp, example of a basic build for snipers would be this:
Rifleman - Level 81
Countdown - 1
Leg Shot - 10
Hiding - 10
Precision - 10
Critical Power - 10
Detonation - 15
First Encounter - 1
Closing Target - 13
Vital Spot - 1
Mark of Pursuer - 10
Stun Blitz - 1
Ultimatum - 1
Sniping Stance - 6
Defect Vision - 6
Fatal Guard - 5
Phantom Buster - 4
Killing Inspire - 3
Death Knell - 2
Ghost Stance - 1
Napalm Strike - 1
I hope this explains why the skill Hawk Eye not be used by many shooters.