Why, oh why, is there not a way to easily Align to Key Object in After Effects like there is in Photoshop, Illustrator, and InDesign? Or am I missing something? I know of workarounds, but why isn't it as simple as it is in other Adobe apps?
Currently there is simply no way to interactively determine these things and everything is limited by the layer paradigm. A simple layer selection does not "see" the actual content to make a determination about the effective bounding boxes of the layer content. That would require quite some changes to how AE works and accesses the layer pixel data.