I only briefly played in one Tekumel campaign. One thing I liked about it (and I'm talking the original Empire of the Petal Throne here) is that it assumed the player characters were foreign barbarians who knew next to nothing about the customs of the place they were going to be adventuring in. It was important for the DM to have read all the necessary fluff, but MAR Barker seemed to have learned at an early stage that a lot of players tend not to even give a millipede-sized shit about that sort of thing. (You can easily divide RPGers into two camps, I think - the ones who are into setting details and the ones who just want to kill orcs. These fairly accurately map to people who like to be the DM and people who want to play. As one of the former, I find the unwillingess to get into the details of a setting to be so odd as to verge on insanity. I suspect from the other side of the coin the reverse applies. But I digress.)
Tekumel teaches two valuable lessons. Namely, if you're creating a Setting Which Some People Might Think Is A Bit Weird, there always needs to be an option for people who want to be Bilbo the Hobbit or Legolas the Elf even if that doesn't fit the setting in the slightest, and there always needs to be a place where foreigners might "start off" and get eased into the setting while they find their feet.
(The third lesson is not to charge over 80 quid for a boxed set.)