i wouldn't call it an omnillussion because the all of the clouds that hit sephiroth are quite real. not to be a smartass by saying that of course.

its more like just super speed and grabbing the swords while they hover on magic and leaving behind golden magical trails.

neo-omnislash seems about right.

Its hard to describe how the move is done because of how quickly it happens, so omnillussion is a good desription and so are most of the others.