Can you explain what this would add? Would the message be marked as "read" when doing this even if you can't see the whole message? I voted no because if the message doesn't get marked as "read" for especially the sender, it would just lead to people reading mails without the sender knowing and possibly take actions before officially "opening" the mail and claim ze hadn't read it before... This could potentially lead to all types of foul play, as if it wasn't enough of that already It's not that hard to just open the mail like normal
I'm not convinced this is a good feature idea as I don't see any value it adds to the game.
Hovering over attacks / reports was useful as a way of scanning it. However, mails should at least need to be manually opened before they can be 'hovered' over, to avoid interference with the 'read / not read' part of the mailing settings. When leading tribes, seeing who is / isn't opening mails and determining activity etc is important.