hazardous examples of what i would use…
1, move all secondary stats to the character.
2, Armor becomes purely Armor and Stamina baseline.
3, armor effect slots are standard.
4, tertiary stats go into the armor effect slots.
5, epic items also have bonuses themed around the armor. like thorns effects. reflections of damage. an absorb shield similar to BFA gear.
6, a heart of Azeroth type slot gets added but it goes into a new slot. this item takes in AP (lets call it Ability power) which is the universal primary stat dump. the higher the level of this item, the more primary stat you gain. have various percentages of currency drop from all content. but basically it maxes out after about 25 mythic raid boss kills. or other equivalent levels of game play. a world quester could grind it out but it would take quite a bit longer. the cap would prevent it from becoming a never ending grind system (though each patch would raise the cap)
so basically gear would be choice effects.
Player stats would be built around What the player wants. if you want it all in crit. go for it but your other stats will be equally as affected with no points. so its the player’s choice.
IN addition, the higher the AP collector level is the more stats the player is given to distribute how they want.
RNG will not be the factor in player optimization from a secondary stat perspective.
maybe all players socket leech effects to be optimal. or maybe they stack avoidance. or speed.
to limit those effects from being the only right answer without nerfing them, add more options to the pool that make the answers less clear depending on the situation.