Mailwire has some good ideas that are poorly implemented.

I'd like to borrow some of the ideas behind Mailwire to create per-module/per-key pluggable settings for every aspect of HTML Mail. Here's a plan for consideration:

  1. Rewrite the changes currently done by Mail MIME and Echo as pluggable filters. It may be possible to re-use the core filter system, or it may be necessary to create a new filtering system that applies to mail messages rather than just text blocks.
  2. Rewrite the HTML Mail settings page as:
    • Site-wide default settings
    • Per-module settings
    • Per-module/per-key settings

    Borrow ideas from the Mail System settings page and the Views "theme information" block.

  3. Implement #1150140: Allow through-the-web editing of templates.