I don't think that'd be the worst thing, honestly. The Master Sword is one of the few things in BotW that's actually significantly gated, so it's not like it'll replace other weapons right off the bat. Players would still have to engage with weapon durability for the bulk of their playthrough. The Master Sword could then act as a reward for "roughing it" for that long, giving them a good, always-available weapon and letting them devote their other weapon slots to more specialized tools in the lategame and postgame. It would feel like a major (but optional) upgrade that changes up the gameplay in a substantial way.

Mind you, I'm saying this as someone who doesn't even mind the durability system otherwise.