What happens if you can use any weapon, no matter your stats? How, you ask?
Here’s what I’d do.
Instead of stat requirements to use a weapon, gate them by level. However, you only get the base DMG of the weapon unless your stat matches the scaling requirement.
Ex:
You have 10 in STRENGTH and 15 in FAITH.
You find a sword that requires 17 STRENGTH, and has a
base damage of 5.
While you can equip the sword, you can only do 5 damage,
and you can only use the first rune in the weapon.
Once your STRENGTH equals 17, the sword's base damage
can start to scale, and you can use all of the sword's runes.
You want to add Burning Slash, a rune that requires 16 Faith.
You can slot the rune in your sword, but unless you have 16
Faith, you can not use it.