We should not go ahead with this renaming. "dual-licensing" is the commonly used term and the term "multi-licensing" should have mariginal or no use in the context of free software.
The tag excerpt cited by the OP is IMHO incomplete and somewhat misleading. In the context of free software "dual-licensing" is a much used business-model that is common enough to justify it having its own tag. The business model of dual-licensing means that in addition to a free software license, the software is also offered under a non-free commercial license (specifically for those who don't like copyleft). Since there are only two options - free and non-free - there is no real use case for more than two licenses.
"Multi-licensing", on the other hand, has not yet been used as a tag. When I search for this term in questions, its use seems limited to questions showing poor understanding of licensing principles, or having only been posted in order to play "what-if" mind games about very hypothetical and speculative scenarios. I don't think this site benefits from this type of questions. Instead we should encourage users to ask good questions about real free software and free culture use cases.
Since "multi-licensing" is not currently a term, discouraging its use is not on the table, but for the record: I do not think "multi-licensing" should be term in the future, neither by renaming "dual-licensing", nor as an independent term.