100% do not have item sockets rerollable by NPC, it defeats the point and is counter intuitive.
If you have a reroll NPC it makes 1 and 2 slot items have zero value, and forces everyone to make every item 3 slot to compete.
It's better to do as Chrons did, and have items drop with slots. That way even 1 and 2 slot items hold value, and 3 slot items are godly. They gotta be rare though, don't want every item dropping slotted.
On Apocv2 there was absolutely zero thrill when even the rarest item dropped, cause it was still worthless... only when tiering, then slotting, then qual orbing, then stat orbing, was an item valuable. You should be able to use an item as soon as it drops, not have to wait for 2 weeks till it betmats your old item.
The dopamine hits / excitement in mir are pking someone, and getting a good item drop. Too much RNG, and expensive outlay to upgrade removes this feeling.
Keep refining for that kind if stuff.