Mutt is more like "everything I can come up with from the command line." Sure, I won't make my grandma use it, but I've never needed any searching capability beyond grep and co.
Not necessarily. Try to do something like write up your email in Markdown, and create a script to automatically convert it to multipart/alternative with text and html versions. So far as I can tell the only 'real' way is to insert the script between mutt and the sendmail command, but that's less than optimal.
Mutt is more like "everything I can come up with from the command line." Sure, I won't make my grandma use it, but I've never needed any searching capability beyond grep and co.