Ashanti - 4 (7 - 3) - Again, no interest. Morocco, Ethiopia, Swahili/Oman are all far stronger concepts within VI's design.
Navajo - 20
Tibet - 18 (17 + 1) - Idunno, I don't hate Vietnam, but I also think its fans tend to focus on pretty superficial or irrelevant things. Like the fact that it resisted Chinese invasion doesn't actually improve its chances since the "stubbornly independent civs" expack was R&F. That ship has sailed as far as VI is concerned, and even then all of the R&F civs had a pseudo-expansionist/imperialist bent that Vietnam never really had, which to me suggests city-state. I'm not saying it can't join the party, but it needs a lot more work put into framing it that many just aren't bothering to do (which, granted, is true for quite a lot of highly requested civs).
Vietnam - 17