I think the feeling for most of us is less about 'need', or necessity, and more about what feels like the best synthesis for BotW's potential. The fact something works does not then preclude it being better, right? So if you accept that, the next question is can the weapon system be better? If...
They could also add more kinds of material. Now that the developers built a framework with BotW I am hoping that they really are able to expand on it for BotW2 and realize BotW's great potential. BotW is an amazing game, but what's even more amazing is what it could be if its potential is realized.
Fundamentally I like the system, but it ought to be more refined. Weapons break too quickly and there ought to be better ways of balancing the game than designing them to break so quickly.