See the screenshot for an example of editing a document in the RTE. This is highly unusable. A combination of the following could solve the problem:
- Duplicate the way that Drupal has expandable textareas.
- Have bigger textareas for fields that use the RTE.
- Have fewer buttons in the RTE (strong, em, lists, a, img and that's it). If the RTE is used anywhere other than for email editing, this is the desirable solution. However HTML emails require tables so we still need the full editor for that.