I think the easiest way to make it more elegant (from my perspective) would be to prohibit empty messages.
I'd rather not, though. Entering text is extra hassle on mobile. Pops up the keyboard, which on older mobiles or ones funking out can bog things down.
Maybe the game can auto-generate a very generic message for letters that have attachments but no text? "Here are some reports", or something along those lines.
