Navmesh-based pathfinding would be very, very nice, especially if the navmesh could come through the EGG pipeline.
The Boids-esque behaviors would be fun too, I suppose, but I personally would be best served in that respect by a simple 2D culling structure and neighborhood query. If you do do the Boids stuff, it’d be really nice if those were a layer over a well-exposed and documented culling structure.