Have you noticed the little triangular grouping of dots down at the lower right corner of the message text box? That allows you to greatly expand the size of your message area by dragging that down. It’s a little clunky, but you can expand the message text area to nearly the entire screen, if you so choose. My only gripe about doing so, is that the attach/save/send/delete icons can scroll off the top of the screen, if you enlarge it too much.
This is a huge improvement from the previous web mail, and any other web mail I’ve used (which admittedly, isn’t that many).
I see your point - there’s about three lines of vertical space each for the To and Subject fields, which does seem kind of excessive.
I’m also not sure why there is a ‘From’ field at all? Are people really using webmail to access multiple Runbox accounts at the same time? How is that even possible, wouldn’t it depend on your login?
We’ve adjusted the vertical spacing of elements on the Compose screen, and made the message body area taller. These changes are now in the pipeline to production.