Is it possible to remove an email template from a managed package release?
I used to want to distribute a template but I don't use it anymore so it just redundant.
You have two choices:
You can roll back to a beta package. Note that you must roll back to the version that originally included the template to do this, and this requires that all customers using any later version (including any sandboxes, demo accounts, etc) uninstall the later version first.
You can request access to the pilot program that allows deleting arbitrary elements from a managed package. You must use this with care, as any elements deleted this way are permanently lost; the "name" of the element becomes permanently unavailable for future use within that package. For example, if the template name is MassEmailUsers, and you delete it, you cannot later decide to create a new template called MassEmailUsers.