I'm still musing over 1st edition Oriental Adventures here. I decided to compare the class options by alignment between baseline AD&D and OA. Here are the classes from the 1st edition PHB laid out in standard the standard alignment format (Lawful Good upper left, Chaotic Evil lower right).
Ever alignment has six or seven class choices, except for Chaotic Good. CG gets the short end of the stick with only five. If you take out the ever-problematic Bard then CN also only has 5 options and the LG and LE become the only alignments with seven class options. Either way you cut it, each alignment has 6 +/-1 classes associated with it. Law is slightly favored over Chaos, but not by much.
Looking at OA, the situation is much more asymmetrical. Dig it:
The Lawfuls get seven classes and every other alignment only get four. This design choice seems aimed at an overall theme in OA: that the Mysterious East has a more rigidly organized societies than good ol' Pseudo-Europe. I'm not really against this particular conceptualizing of Totally Fake Orientland, but that uneven distribution feels pretty odd compared to normal Gygaxian set-up where every alignment has a fair share of the goodies.