Savok is correct in stating that this thread presumes detailed characters are turned off. This does mean you lose the glory of seeing little 'E's all over your dining hall that you engraved shortly after the elephantine slaughter of aught-five, and the ampersands are completely absent from the treasury built in memorium of Drom 'Pickhead' Holterfeist after his fruitless search for more gold led to other discoveries...
But, even still, detailing has a feature to it that smoothing does not. Detailing is directional. So when you detail a wall, only one side of it actually gains value -- the one that faces the engraver while she does her job. I appreciate the aesthetic considerations here, and the game perhaps should show the corner as engraved until it's dug next to. But the implication of an engraved 'look' is that the room's value has been increased when that would be impossible. In the case of a wall such as:
code:
|..
***+..
...*..
...*..
Presuming asterisks mark walls detailed inside of the bottom left room, automatically detailing the corner here would imply that the right room has an engraving increasing its value, which it doesn't.
Clearly, we just need four dimensional displays for our ASCII to resolve this nuance, and, given those, I'm certain Toady could solve this nigh instantaneously. I've designated my hammerer that it's her job to hold her breath till this happens.