It's frustrating when you want your units to go one way but your buildings are facing a different direction. For example if your trees or mines are behind your cc, all the extra walking adds up. When placing buildings you can try to orient them in the best direction, but sometimes what's "best" will change throughout a game.
Since units can garrison (and drop off resources, etc.) from any direction, they should be able to ungarrison from any direction too. Some buildings have "doors", but they're not all aligned perfectly with the center of the front of the building, and units don't actually interact with the buildings by walking up steps or through the doors (with the exception of standing on walls). In my opinion gameplay should have more weight than "realism", so I think being able to spawn in any direction is a good change. But I understand some people may feel differently so this can be a discussion.
Here's some screenshots of the rally point direction:
The current code tries the same number of points regardless of how big the footprint is, so units are more clustered around small buildings than large ones. Also, the spawn area is really large, so units (like rams in the screenshot below) can end up being far from the building if there are lots of units in the way.
In the patch I've adopted a more uniform approach to spacing, plus I've restricted large units to one row around the building so that they can't spawn a far distance away (instead you'll have to move units away from the building so there's room for them to spawn).
Let me know what you think.