currently the best 6 stats are primary ones + damage reduction if you want to be defensive style or critical if you want to be attacking style. Elemental resistances with +2s ar simply meh...

Why damage reduction and not elemental resistances? If you are able to stack on your 10 tools 800-850 damage reduction (the max possible right now with the current tool essences + red reforged tools) you cut all the damage you endure by 6% that is the same exact outcome you will get on elemental damage by adding 3 +2s for 5 elements, and this requires just 10 slots used vs the 30 used by the elemental resistances with the not slight difference that you also cut the non elemental nin damage and the tai damage by the same quantity.

Elemental resistances become comparable only with +4s.

When kage ti will be again available the best option for full defensive style will be damage reduction, defense, resistance, life and +4 elemental resistances on the other two slots is you are able to get full matching natures on the tools. Otherwise you forget about resistance and life and you fill those 20 slots with other +4 elemental resistances.