I don't think it would make sense unless (like someone mentioned in here, iirc?) it was a specialization or trait locked to a specific element. The way ele is now, it's already sorta like they have 4 weapons to swap between, just you're range-locked as far as that aspect of it goes. Which is a tradeoff I'm generally fine with. There isn't much benefit I've seen to being able to swap between ranged and melee specifically, in other classes, since the weapon skills don't necessarily match for the same build to begin with. In other words, switching alone may not mean much anyway, if the weapons you're switching between don't synergize.