I notice some routes or areas indicate which direction the wall faces but it's written into the description or someone's comment. I think it would be nice if it was part of the specifications for an areas (Elevation, GPS, etc.).
When creating or editing an area, it would give you four check boxes: North, South, East, and West. Allow selection of up to two directions to indicate directions like southeast or northwest.
On top of that, add a filter option on directional orientation. For example, "It's winter, I want to hit south facing walls so I don't freeze my ass off." Filter routes to show only south facing walls. Or, "I know there are going to be some west winds tomorrow." Filter routes to show only east facing walls.