Using SAM for Kin why? WAR is best.
Probably because it's content that is so easy now, that fun factor is more important than min maxing for efficiency, so everyone will use whatever job that provide most fun for each person.
I would argue BLU is way better than WAR, because you can aoe faster and it's where you can save more time than on boss itself and for boss specifically MNK is probably the best by far because it reduces time where Kin absorbs physical damage.