“‘Hackers’ is a term often used to cover people partaking in a very broad range of activities, like exploiting game bugs/mechanics, stealing another person's private account information via keyloggers or phishing, and infiltrating a system's security to gain some level of control over the system or sensitive information held therein,” said the developers in a post picked up by MMO Champion. “The latter of the three is most accurately described as hacking.”
Multi-boxing doesn’t fit into any of these categories, Blizzard suggest, and so doesn’t necessitate any preventative action - provided the player isn't using any macro scripts that automate gameplay “beyond what is allowed through default macro and API specifications”.
But the developers have no plans to make the practice any easier, or any less expensive.
In short: nothing’s set to change here. Let us know your opinion in the comments.