Board Thread:Support Requests - Getting Technical/@comment-25463843-20161112114857/@comment-24473195-20161112122213

Loads of existing extensions don't have support and aren't editable in visualEditor. It is not just poem, but, and much much more.

You can try to convince staff to backport this functionality from the newer VisualEditor, but as the poem tag doesn't really get used that much except in specific wikis it will probably be the lowest  possible  priority.