Equipping a weapon/shield could return your currently equipped weapon/shield back to your hand, rather than simply destroying it. I feel like overall it wouldn't be too powerful, perhaps except some notable combinations, but I think it's a concept that's more fun than it is powerful if anything.
To keep a handful of weapons/shields and rotate them out if the situation with your opponent changes. Especially with all the cool new shields
Extra considerations: stackable shields would need special rules to prevent infinitely rotating to easily gain stacks out of nowhere in exchange for quanta. Altered states would have to be retained to prevent swapping out damaged or status'd weapons to easily heal them. And probably a lot more undesirable interactions that would have to be accounted for.