It might … however I would consider this as abnormal for UX design concerning menus, so it could also confuse.
What you propose is actually more alike a dropdown picklist (yes, like the one in the Entity Info panel,) which would say "<varies>" when there were multiple tags for the items in the selection.
This would mean a popup html dialog (which I think Curic has done,) rather than a context submenu.
It is a lot more work coding a html dialog.
Paul’s plugin grew from a simple example, which he “simply” tweaked for his own use. I helped clean it up, and added a simple “Create new tag…” command, again as part of a coding example of how to conditionally add or not add menu commands based upon the current editing context.