I think the "Talk" or "Discussion" pages on MediaWiki sites are mainly intended to discuss the content of their respective pages, whereas I assume this proposal is meant for general questions about MediaWiki sites/software/server itself as a whole (judging by the example questions – although I see that the proposal's description doesn't ...
I don't think a dedicated Kali Linux site will be viable. Experienced users will be able to get answers they need on sites such as Security.SE and Unix.SE, while beginners generally picked the wrong distro for what they're trying to do.
Rhetorical question: Why do you need others to participate any more? If there is no interest, if people just don't have questions to ask, then there is probably just no need for this proposed site. That's the most honest feedback you can get.
I don't see any useful purpose in pushing a proposal artificially.