I'm glad there is a visible grid now! There are a lot of uses for it (though admittedly fewer for my game <img src="smileys/smiley17.gif" border="0" align="middle" /> ), but I would pick new/improved features over updating the sprite editor any day. There are so many better, free options for graphics creation and manipulation that it seems strange to make it too full-featured.
I agree with you, just figured that the code for visible grid in the layout could be reused for the sprite editor. I only use the sprite editor for standin graphics when prototyping, but with a bit of dev love here and there, it could be used for finals.