I'd like to see a border tool added to the visual editor.
Today I have to manually code or copy/paste the code to add different border styles and thicknesses. I think it would be very productive to have a window that allows the user to select TOP, BOTTOM, RIGHT, and LEFT styles and thickness from a user interface based on the cell they currently have selected.
<TD Style="BORDER-LEFT: black 4px double; BORDER-TOP: black 4px double; BORDER-RIGHT: black 1px solid">
I realize after writing this that i forgot the color option but think it should be a single selection applied to all four selection, as you wouldn't too many cases of multicolored borders.