You see the Art Director is the one who pretty much makes the initial designs and what not, he sets the mark to which other artists must meet, the AD then assigns different aspects to artists and instead of doing the work he makes sure they adhere to his vision, and making sure they stick to the schedule and standards set by the top guns (i.e : publisher or perhaps the boss of the developers).
This impression of lack of practical involvement is something I've still kept while reading the various articles from blackboard, as much as they enjoy it I'd probably lose interest in such a position over time, yes it involves a large amount of creative control over artists and what not, but it’s more of positioning the time and roles of artists and watching over them in making your vision...I guess I'm a bit too hands on in that when I want something done in my vision I prefer to be the one doing the tweaks. Also the qualities a Art Director must have are rather demanding, to become one alone is a daunting task, first they must show they have the technical skill and creative visual flair as well as being able to show good office skills in managership and probably have a voice which won't be drowned in the hustle and bustle of the office.
As for Art Directors compared to Movie Art Directors I think the roles are pretty much the same, except the people they’re in charge of would obviously differ yet in the end it would still be them taking care of scheduling and making sure that everyone adheres to their creative vision.
However I don't think I'd turn down the position either if it was offered, it still does seem like an amazing job and you never know by the time I reach that level of epicness I'll probably be a lot more confident and able to handle the job but for now I still think I'm too quiet for such a job. And hopefully capes and sunglasses would be the traditional wear of Art Directors by then.