ToME: the Tales of Maj'Eyal

e.g. strength 43 --> 49 with a +6 str ring, wear a mithril sword, take off ring, strength is back to 43 but weapon is still active.

Maybe if stat falls below required talent/weapon/armor, state "Your weapon suddenly becomes too heavy to wield!" (drop in inventory)

-or for daggers "You suddenly feel too clumsy to confidently wield the *** dagger!"

-or for staves "You suddenly struggle too much to harness the intrinsic energies of the *** staff!"

-or for talents "You have forgotten that talent."

Not sure with the talents such as Health and those things--I know I've been abusing stat boost items to get it

True, that's a tad hard to do, but I'll do it someday

I don't think it should drop to inventory. (In fact I think one should be able to use all items that you're not proficient for)... But it should make you unable to attack (weapons) or move (in case of armor). Dunno if rings or amulets have prerequisites but they can be worn but not gain the benefits.