Would it be possible to have an export option to map the snap points to an empty axis in Blender? This would make moving parts around easier and it would be especially useful for rotating objects while keeping them aligned.

Better yet, as to not fill the model with a lot of extra data, create empty axis where custom origins are set or something similar.

Another option could be a panel of blender helper objects that you could add to the lego scene that would map to empty axis, light types, or other objects.

Also this topic may be better placed in the export and render forum...