I mean that if you were normalizing when setting the coords directly, it would be relatively more expensive.

https://github.com/DDoSQc/SpoutAPI/blob/541a681e6525a00983d8f3abb19541458d9b46e6/src/main/java/org/spout/api/math/Quaternion.java#L76

The fact that there is a sin() call means that also having a sqrt() has less relative effect.