Rita posted an interview with so WG designers (Or whatever) a week ago or so. I can't link to it because of settings. They said Chieftain not coming anytime soon and will not replace FV215b. Hinted they had some other idea in mind. Rita asked about player concern of it becoming a Clan reward tank. They responded why is that a problem or something close. So that is my Chieftain issue.
I can get a Chieftain in AW but not in WOT if it is a CW reward tank. I posted something on this in the WOT topic. There is also a save the Chieftain post on the feedback and suggestions area of the WOT forums. Although it is getting little attention.