(For me) it is not obvious how to delete a page.

I might be able to reuse some pages, but occasionally I would like to entirely eradicate e.g. a misnomer.

Doing so from within the wiki (as Admin) does not seem possible and deleting their corresponding directories leads to annoying errors (which I don't know how to fix)

I agree. There doesn't seem to be a way to delete pages! Fairly basic functionality I would have thought...