like all DD you should consider to boost.. skill pwr/crit dmg and attribute (became very important even in PVE now).. m.atk is always good to raise, but for nuker not biggest priority for dmg. With nuker its a good boost to raise INT (for m.atk + crit dmg), so getting rings with INT is a good option. The advantage with nukers its the m.skill and m.crit dmg are same boost, tho crit rate are capped.. so no real need to increase crit rate, since you max out easy. But you should put some focus on attack attribute/forgotten skills and OE skills.