Make it so you can equip any weapon, no matter what the requirements are. However, and this is key, the weapon’s damage is affected by it’s requirement, and only when you invest in that requirement does the weapon output it’s potential.
Simple example:
A sword drops and it has 20 strength as a requirement.
You have 10 strength and the output damage is hugely nerfed, BUT you’re able to use it.
So let’s say it’s damage is at 10%. Every time you invest in Strength, the damage goes up 10%, up to 100% when you’re fully invested.
This way you can try every possible weapon and gives you a reason to invest in the points to make it 100%. 
