Guild Wars 2

Assuming weapon swaps were disabled for Elementalists because they can attune in combat is a good idea. However, due to the design of weapon variety and skill variety, Elementalists should be able to swap weapons instead of having to switch using inventory outside of combat.

In other words, this provides all the benefits of swap other classes have out of combat, without having an impact in combat.

YES, YES!

I want this on my Engineer so hard. Totally supporting this idea.

+infinity

I find this a very good idea.

Additionally, by not having a weapon swap option, Elementalists and Engineers are also disadvantaged in inventory space: since they cannot store their spare weapon set in an equipment slot, their spare equipment takes up bag space that other professions have available for other things.
Add to this the fact that both these professions also only have one underwater weapon choice, so they have a full three spaces of inventory less than any warrior.

This is a minor not-so-obvious implication of not having a weapon swap available.