I think the only WOs in Army Medical Department would be repair persons. The last WOs in patient care, AFAIK, were PAs and they made them commissioned officers when there became a problem of the Nurses outranking them.
I think Dustoff pilots are MSC WOs instead of Army Air Corps.
I remember years ago seeing an ad from the Navy trying to recruit associate degree registered nurses as warrant officers. I sent it to my sister who works at a community college with an RN program. I've never seen anything about it since, so I guess it didn't work.