I upvoted your response as your ideas are very reasonable but as for me, I don't like e-mail for a number of reasons, both psychologically subjective and technical.

The first things the e-mail ecosystem is to do to become more adequate to the modern day world are to deprecate all the codepages but UTF-8 for any part of a message (header included), eliminate the overquoting tradition (including full text of the message the message is a response to) and introduce an efficient thread tracing mechanism instead, establish a more reasonable signature culture (i.e. people and software to stop including redundant and useless information in the bottom of every message) and make Markdown a core part of the standard (while HTML should better be deprecated).