[Nami]

Hello.

Empowering skills depends on your play style. I assume that your main skill is Power Hit considering your choice of statbuild. Increasing your damage, decreasing your cooldown and SP consumption on Power Hit would be wise.
A fully empowered Power Hit is 15 skillpoints, and it's arguably worth investing 15 points in Power Hit.

Increased damage: Your burst damage will be increased MASSIVELY if 5 points are invested.
Decreased cooldown: This choice will increase your DPS significantly. (Damage per second).
Decreased SP consumption: Last longer in PvP (No consumption of stones and pots). Saves alot of money in the long run (Saves you pots and stones), PvE wise.

Sincerely, Nami.