Many decades ago, when we had Netscape Communicator, we had a proper HTML composition application for that time. Since those wonderful days of experimentation on the internet, we have transitioned away from the rich look and feel of HTML messages. From memory, a small group of developers decided that all e-mail messaging should be done with "text only" messaging.
If we look at the international scale of e-mail traffic, we will note that the bulk of commercial advertising through e-mail is done with rich HTML coding. Is there something Wall Street knows that Silicon Valley does not?
I would like to see a team of talented engineers tackle the problem of creating an exceptional HTML editor for Thunderbird to enable the richness of HTML content in outgoing e-mail messages. With the thought in mind of porting this out to Firefox for creating web documents and Seamonkey, the all-in-one internet suite. To appease anyone who still thinks text is the only way to communicate, include a preference in 'settings' to place a button in the compose window to turn on/off HTML/text.
It is a big time waster to have to create rich HTML in a separate HTML editor, proof it for errors, and then open Thunderbird and use the "Insert HTML" button. With modern technology and the new HTML 5 available, we should be able to create responsive e-mails better than the big guys on Wall Street.