"Concentrate" is underwhelming and weak (additional Phys. Range DPS skill)

[Fannah]

To the cost of an Additional, the best dmg bonus the skill will provide is
on Bard : +480dmg on Apex arrow (if you use it with max jauge (100))
on MCH : +400dmg on Drill or +550dmg on Drill (if the target has Wildfire and Bioblaster)
on DNC : +360dmg in AoE on Saber Dance (the best and easiest to use imo)
With 30sec CD, with so low bonus dmg, I believe it could be at least 15sec CD.

Meanwhile we could choose a skill that Bind someone for 3sec (30sec CD), or that inflicts Heavy for 5sec (30sec CD), or one that heals you 3000HP + Removal of CC (Heavy/Bind/Holmgang) (45sec CD) or one that makes all your team run away more safely (60sec CD).

It might be the very small difference in a burst between life and death of your target, but I believe it's really underwhelming, especially when magical range DPS have
Phantom Dart --> +20%dmg for 6sec (3GCD) + 1000dmg
Drain --> 600dmg and heals you 1200 minimum up to 2000dmg and heals you 4000 (2400dmg and 4800heal with Phantom Dart)
Aetheric Burst : 600dmg in AoE and " Lengthens weaponskill cast time and recast time as well as spell cast time and recast time by 10%" for 10sec.

It's a bit less comparable but melee dps has Feint that upgrade their dmg on the target by 25% for 6sec.