Ideally, it would also keep the revision history for each page.
No need for ACLs, attachments, or users.
The wiki markup should either be converted to MoinMoin’s syntax (maybe in a second step, when all pages from WikkaWiki are exported as text files), or there should be a MoinMoin converter I could use to continue using WikkaWiki’s syntax.
I don’t have the programming knowledge to write this from scratch, but adjusting a script that comes close should be okay. If there is no tool doing this, maybe it’s possible by adding an intermediate step, e.g., WikkaWiki → MediaWiki → MoinMoin?