The wu jen (OA wizard variant) has magic based on the Chinese elements: fire, water, earth, wood, and metal. Note that air is missing.
The shugenja are "divine spellcasters who cast spells by attuning themselves to the elements around them and focusing the power of the
elements through their bodies to produce magical effects." In Rokugan, they attune themselves to elemental kami spirits. They focus on the Japanese elements of earth, air, fire, water, and void.
Both class models have good flavor. However, I have to wonder about why there would be this dichotomy in a fantasy world. In Rokugan, there are no wu jen, so no big deal. However, the wu jen and shugenja are both available in any setting with an Oriental Adventures theme.
This brings up some questions.
- Why the difference?
- How would wu jen and shugenja relate in the same setting?
- Should they be combined into a single class?