This is exciting. A compelling FOSS alternative to Atlassian Confluence was sorely needed. Mediawiki has some UX and RBAC challenges that makes it difficult to scale to large organizations.
"Some"? The fact that you have to manually access the database backend in order to change a password is a joke, among many.
To actually set someone else's password to a specific value does require running a command line script (not the same as going into db). In my view that is a reasonable security-convinence trade off.
In any case, i would assume a large org would use a single-sign-on extension and not mediawiki's native user management, which would make MW's password management moot.
Disclaimer: am mediawiki developer