Right now there are no adjustable mailing templates in mews only adjustable mailing "contents" which is incredibly weak and a bad hit for corporate design and even the customer journey (reduced trust because its in a completely different design than anything else). For a pms that is centered around the customer this should really be different!

I think it would be useful to add an global option for template and probably even for each individual mailing. So you could adjust this for single mailings if you want (which is asked for in different ideas).

You could use a single settings field in which you could copy a whole html template (for example from our newsletter provider) and only add an placeholder/variable where the content (defined in the singular mailings) is added. If you dont use this field in a singular mailing the global setting is used, if nothing is set there the standard mews template is used (works in a cascade).

If a mailing is defined mews shouldnt add anything else around that. Styles that are needed for individual mailing contents should be added probably there.