Some ideas to make the upgrade system less rng and more hard
- You could use a upgrade level requeriment to improve your chances of succefull upgrade a weapon.
- To increase the upgrade level use some kind of stone (you should choice betwen use a white stone to aboid the broken or use the exp stone and gain exp of upgrade) This way you to reduce yout rng playing the game.
- Upgrade anythig need cost zenni and "upgrade level" in relation with the weapong level.
- Delete all the "dowgradeable stones".
- Downgrade a gear (having bad luck ) weapon should always reduce your "upgrade level"
- Use "broken" to downgrade your weapon to +0 always or at least -6.
- Put a counter in all gear
Give +1 to that each time that the gear has been downgrade,
Wich each counter the weapon gain more "resistence" to the upgrade (reduce the chances of succefull upgrade). This make new drop more value and keep alive the farm in time.
-Make a "increase chances of succefull" stat for gear.
You should need to craft your own "upgrade gear" to get better chances.