all Main is good, but u need good ninja for make great line up. Im MB, but now i change to water since i get ningendo.
for water main (im lv 83) i use
x x x
x ningendo AF
gakido darui x
talent 4,4,2,4,2 pet Dog Of Hell.
u just need have high initiative and win all PvP, i see u have good power for lv 79. just make u'r all refine at move 1 is lv 7 / 8, move 2 (if nuker ninja like me) have refine lv 4 - 6, and move 3 have refine lv 3 - 4.
for now i like water main cos have good crit and dmg, and have misery just need 20 chakra. so i can counter enemy if they have healer/canceler debuff with my ningendo at round 2.