a 2 circle swordsman with level 15 Concentrate + its skill attribute level 50 would give a total of 126 extra damage.
when the character level is high enough, 126 extra damage will be a insignificant fraction of the sum damage from a normal attack.
even if theyd have the attribute reset scrolls after release, it would still make one wonder if its worth spending the time and silver to focus on maxing skill attribute for Concentrate to level 50.
the only reason i can imagine using this attribute for is very low level grinding, so if someone is interested in going 3 circle swordsman for the damage buffs, id say nope, not worth it at all.
this applies to gung ho too. at the end (around level 200) theyll make no difference, just irritating having to use them every time they go off.