Different movesets / abilities / stat affixes on weapons like many other games do. Or more enemy types that are more greatly affected by different weapon types.
It's like arguing that all pokemon should die after 2 battles as an incentive to collect and use more.
It simply doesn't work
Variety is cool and all, but it's usually happens to fall behind favoritism
The Moment you find your preferred weapon, all of the variety presented in the game loses its value and player only goes after the better kind of his favorite gear
Dark Souls games prove this really well. but it works in Dark Souls because of its linearity and scripted Item Droppings.
in BotW if you try to approach the Gears with favoritism, The Game makes your work 10 times harder to maintain your favorite kind of gear and make you question your ideals to finally just give up on the Damn Cool Scythe you were using for a while and just try the Stone Crusher.
It puts a very sour itch on player's mind and memory, but in action it just make the Combat a lot more fluids, a layer of misfortune that doesn't break your game or giving the Enemy any advantage, It's only there to make your preferred combat methods goes to vain and making you try again for a solution
It's Genius at the end, I don't think combat in BotW is in anyway the most open-minded and Clever Combat systems out there, far from it, but by blocking favoritism "Brutally" it force you try the other ways of fighting. Other games give you more variety, but don't give you any reason to try the them all.
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all said and done, the system has many ways to improve and be better.
showing the Durability in some form
giving some hard but possible way to maintain the weapon's durability to make the favoritism method possible, but very hard and unforgiving
Give some types of weapon a complete advantage in this regard to make "weak but durable" builds possible
at the same type make some gears extremely strong but fragile to make the opposite builds possible too
and yeah, more crazy variety in weapons and their movesets make the Breakability system more valuable