For summoner Primalist, the only uniques you want are extra wolf amulet and possibly extra companion helmet.
There are 2 areas you should devote your gear affixes to: defense and offense.
For melee/caster types offense includes attack/cast speed, damage, critical chance/multi and the like.
Summoners have minion damage, minion health and minion dodge rating instead.
Defense includes glancing blow, dodge rating, vitality, elemental protections, health, block affixes (chance/protection/damage reduced).
IMO, Glancing Blow Chance is worth going for, for any build. you want 100%, there are 2 different prefixes that give up to 15% each (22% for body armor), so you need 6-7 good rolls on your gear.
Dodge Rating is debatable. You want at least thousand, and that’s too many affixes to afford, unless your class/build can stack DEX or has passives that increase dodge rating (Beastmaster).
Ward is only viable for INT-based classes (mage, acolyte). You’ll need to stack INT and take ward retention passives.
What’s left is effective health in the form of health + protections.
there are 2 ways to go: stack health or stack protections.
If your class/build has passives that increase health, go for max health (necromancer has Tyrant). if you have bonuses that increase protections, stack protections (vitality, elemental protection, “Glancng Blow Chance and Armor” for armor. Armor affix per se is not worth it IMO). Druid has passives that increase protections and armor.
The general idea is to maximize your effective hp (sum of health and protection against certain element). Argument for health is it “protects” against all types of damage, and there are many affixes that help to stack it (health added, health increased, glancing blow chance and health, set health). Argument against health is you’ll need to restore health to survive. More health means your potions/leech/heal/life gain will be less effective in restoring your health to full. This is argument for protections - they “take” part of the damage that you don’t need to restore. but if you want to stack protections instead of health, you’ll need to pay attention to all of them (there are 7 kinds including armor).
stats are not worth stacking on gear IMO, except vitality for protections and INT for Ward builds.