I like this idea, though I’m not sure how it would make much of a difference. It’s never seemed like the characters in the show have acknowledged being able to see the aura of magic.  I believe the magic aura to be an aesthetic way of showing it to the audience, but not the characters, kind of like the airbending in A:tLA.

That being said, it stands to reason that shapeshifters would work to change their aura if it is visible.