How many audiences does your implementation of SharePoint have? I'm trying to communicate to my management that audiences are powerful tools for content filtering, but collectively we're getting hung up on the idea that we might have dozens or hundreds of them, and that this might be onerous to manage. My contention is that for a large SharePoint farm, having many multiple audiences based on AD Groups or User Profile properties would be normal.
I work at a university, and I think it would be a natural fit for audiences to describe academic programs (ex. "Bachelor's Degree in English"). The perceived complexity of our audiences would be describing our real-world environment, nothing more.