Daomei, in the french forums there's a thread in which a support team member states it was thanks to the contribution of a volunteer dev that this could be done in the same day as the patch (ie. having the mobs also aggro out of team healers). So no, I don't think it was planned from the beginning.
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"We are Kami. We are here to be you. We are many as you are of many minds. We are one as you are one in Ma-Duk."