I appreciate your efforts to maintain and support the wiki as public infrastructure. I don’t mean to belittle that work or it’s impact. I know what that work is like 
At the same time, to be practical and prudent, we need to be honest with ourselves.
Wikis had their time and place, but that time has moved on. A resource like wiki.haskell.org can be safely replaced with better means of accomplishing the goals the wiki intended to fulfill. The wiki may have served it’s purpose well in the past, but it can no longer compete with alternatives. For example, GitLab and GitHub both offer better options for signup, posting content to the web, moderation and reviewing changes as a group, maintaining transparency, etc, etc. The same can be said for static site generators, which even haskell.org is maintained with. There is no benefit provided by the wiki, it is simply added weight we don’t need to carry.
Rather than dropping the Haskell wiki, please consider adding content to it.
I have, and I don’t think that’s the place for me (or anyone else) to add content. I believe the haskell.org website and this discourse instance (and people’s own personal blogs) are much better places for the content that is up on the wiki.
This is a good place to refine content that can be curated later into a complete and authoritative guide. For example, the GHC gitlab wiki contains some general usage information that would be more available to users in the wiki.
I disagree, and I believe it would make a lot more sense to
a) use git and the git workflow,
b) use markdown (or whatever the guide’s markup will be).
Please consider adding links to your blog posts, github projects, etc. on the appropriate wiki pages (or add new pages as needed). The wiki is a good place to save these connections where they can be discovered by interested readers.
I believe this discourse instance is a better place for those types of posts (as well as other resources such as the haskell.org website the haskell weekly newsletters, reddit, etc).
It’s ok to let things change for the better.