I wouldn't argue that it lacks overall rationale; I just don't think it's all that clever. These kinds of 'pro' and 'con' decisions are the bread and butter of game design. I don't think converting weapons into a currency is especially inspired either. In fact, given the rest of the game, it feels lazy and underdeveloped: it's easy to imagine a system that makes more sense within the world, with different types of weapons interacting with the world systems in different ways: brittle metals that shatter in the cold, untreated metals, like iron, that rust when you get them wet, steel swords that get too hot to handle in the desert. Rusted swords could be polished up to make them sharp again, you could find some kind of 'oven mits' to handle hot swords in the desert.
Then you open up the chance to consider things like tempering an iron sword with coal and heat to make a steel sword. Creating alloys like bronze or brass from base materials.... And this is just me spit-balling on a game forum.
With the exception of catching lightning during a storm, or a fire sword heating you in the cold, weapons largely exist outside the world systems, which is a shame, because everything else works directly with these systems, giving you tools and options to mitigate for the conditions you're dealing with. Meanwhile, all weapons but one, just shatter after a fixed period, never to return and that's it, that's the depth of the mechanic. A missed opportunity in a game so reliant on emergent gameplay and system interplay.
a more in depth interaction with the chem system is always possible, but the examples you cite kinda devolve in a "red light, green light" state that, at least put into words, doesn't sound too compelling.
what i mean is that in your examples there's no actual choice.
you CANT' use brittle swords in the cold, i'll bring another
i CAN'T use iron in the desert, i'll bring other
emergent gameplay starts when there are alternative options with different pros and cons...otherwise you are only proposing an apparent choice to the player, not a real one. On the other hand, Take the cold system in botw, you can:
cover yourself
bring a fire weapon
eat spicy food
again, the choice is multiple and interact with other chioices you made in other systems (fire weapons take space in inventory, food needs resources to be cooked and it's effectiveness is limited in time and special clothes are acquired through shrines usually).
you discarded this kind of design as "bread and butter", but you would be surprised at how many games utterly fail at gameplay design this way...a big example is the first red dead redemption, where the economy system is completely fucked, shops sell you weapons and horses mainly, but both can be acquired for free for very little effort, the first just by playing since enemies drop their weapons when you kill them and kill is all you do in game, so you are bound to always be stacked on ammo and guns, the latter just with a lasso and walking like a little bit out of town to find some wild horses to tame.
And even if these were not an issue the fact that every person you kill drops money and you are constantly attacked by SOMETHING in the game, means that activities made to make you gain money are also absolutely useless....why would i spend time hunting, skinning and going to a shop to sell the pelts while i can gain the same amount of money just by traveling from point a to b because i'm bound to cross some bandit camp or something?
regardless, i'm not saying yours are bad ideas, there's always more mechanics you can add, but balancing them in a way where they work perfectly with each other and the gameplay loop "works" is anything but mundane.BOTW has been tested to death since early in development, and that's why its mechanics are so well balanced with each other...it's completely fine to not like a mechanic, but that doesn't make it bad for the game, it just doesn't make the game for you...like i said, i hate stealth, but i will never said that MGS would be better without it
