Thanks Phil, that is definitely another possibility. However it looks like the transform effect solves most of the problems, and has a fast workflow, so I'm building presets for each move (slide in from bottom, slide in from left, slide in from top, etc). The only drawback is the transform effect doesn't include z space so I'm limited to 2D moves.
Ideally what I think I'm looking for is some kind of expression that says "at beginning of layer in, move the layer from 2000 pixels below current value to camera height, hold and drift slightly upwards, then ease out to value 2000 pixels above at end of the layer" - and be able to do this left to right, etc, including z-depth changes.
-TG