Moreover the caste system realistically should stifle a specialist economy because it prevents people from pursuing the professions they choose, therefore nipping in the bud countless talented people.
I thought I should comment on this - I've been working on an RFC modmod of mine for a long time now, and I'm planning on implementing the Caste System for India also - except mine would give them -33% cost modifier when hurrying production. If you've played with a highly slavery abusive civilization, you'll know that's not necessarily a "power" but a benefit you'll have to balance. Meanwhile, the Pyramids act as Sacrificial Altars, lowering population hurrying unhappiness by 50% in all cities. India's 2nd UB would do this also, first would increase city happiness. Would this be as offensive?
I haven't been following this thread for ages though so sorry if I'm interrupting something by bringing up something unrelated.