Simply requiring the existing AppleID password to change it in the first place would resolve this issue already. If the thief chooses to reset the password, a mandatory 60 minute wait time would prevent them from using that as a loophole, giving the account owner a chance to wipe the iPhone remotely.
Let's not forget these attacks worked only because the owner of the phone wasn't able to gain access to their own account to wipe the stolen phone when they attempted it in a matter of mere minutes.
The problem is really that Apple wants its users to store their entire personal info, contacts, credit cards and whatnot on these devices and let's you get away with a simple PIN code that if spied let's a third party unlock everything at an instant. That's bad design, plain and simple.
Nobody can convince me that Apple as one of the biggest and most successful tech businesses in the world with an extremely valuable brand to protect couldn't have foreseen this happening. With how much of a fuss they make about protecting their user's privacy and whatnot, saying this works as intended and is the user's fault is not in Apple's best interest.
Now that this info is public and anyone stupid criminal can abuse the woRkInG AS dEsIgnEd flaw, it won't be long for more cases to become public and Apple knows that. I bet they will silently fix the design flaw and won't say a word. One day you'll change your AppleID password and you'll notice some new security put in place. But when calling Apple they will never admit why that feature was added.