More and more agencies are becoming digital and more and more digital shops are becoming AOR's. [If you doubt this, check out Fallon’s new tool Skimmer. Ad agency as a web developer? Very cool.] So, what does this mean for Art Directors? They need to understand animation, be able to talk about it, share ideas about it, understand what it looks like. You get the point. They aren't going to have to animate anything, they have developers and animators for that. Although, it wouldn't hurt. However, AD's will need to know how to talk with an animator and come up with ideas of how the animation works and what it looks like. The animator will have ideas on how something works, as well. But, it's the AD's responsibility to have the final product look like the way that they want it. This I didn't know until I got here.
So what does this mean if you're in portfolio school? Start by understanding the things you watch. Be able to communicate an idea. Don't rely on adjectives like "cool" to do the heavy lifting. So much of this job is persuading. And so much of persuading is being able to communicate clearly.