even with perspective rotations you don't need vertex shaders for correct rotation.
the rotation that is applied to the emitter node itself can be set that the emitter node faces the node again the same way as before (if we give the node a direction) and it will look the same as the original one as the "center plane" (if you would project the whole emitter onto a plane perpendicular to the line camera - emitter) will be oriented towards the camera again.
the rotation that is applied to the emitter node itself can be set that the emitter node faces the node again the same way as before (if we give the node a direction) and it will look the same as the original one as the "center plane" (if you would project the whole emitter onto a plane perpendicular to the line camera - emitter) will be oriented towards the camera again.