One of the stepper brackets (for lack of a better name) finished printing, so I went ahead and installed it.

Here it is from another angle:

And this angle shows how little it interferes with the belts:

This addition completely removes any play from the stepper motor, before this it tended to wobble around due to it only being held on by one point. There is room for improvement in the model, however, because while it functions nicely it is a little bulkier than it needs to be, and could definitely be streamlined. I may print a standoff to cover the exposed screw on the other side, mainly just for aesthetic purposes.