I think it's great that the message box can now have its size specified. Unfortunately its the same size in all contexts and on the game boards I find that more than 4 lines is too big (given that I mostly don't use it), while on the discussion boards 4 lines is too small. Going back and forth to the Change message area size is a cumbersome workaround.

What would be really handy is an extra javascript capability - a button to immediately (but temporarily) resize the message box. Or for it to expand to a designated size when it gets focus, or when there's a subject in the subject box (which would encourage people to actually provide a subject) .. or some other such big-only-when-required mechanism.