FYI: I implemented bug 30888, which allows users to see mails in plaintext only.
I am also working on bug 108153, which allows to strip unwanted tags from incoming HTML. IMO, this is what makes HTML mail useable, because it removes most of the security and privacy threat and can also remove presentational formatting. Left can be only structural HTML, which is IMO superior to plaintext (if used well), because you can e.g. have URLs and quotes without guessing and nice wrapping even in bulletted lists. Ben Bucksch
