I think the name should definitely bear (is that the right bear/bear?) the VMK acronym but should distance itself from "the game that must not be named."
Make VMK a noun referring to the original game and not an abbreviation, then assign a new word at the beginning or end that refers to a genuine VMK experience. Like maybe "The VMK Experience" or something. This way VMK doesn't actually mean Virtual Magic Kingdom its simply a synonym for the game but does not actually use the term "Magic Kingdom".
I feel that by retaining the VMK name in its entirety in some fashion it will be easier to explain to people and attract old friends back to the game. We had just gotten started finding our old friends in "the game that must not be named" before "the incident" and I'm sure many more will come back over time if they know what to look for.