Is it even worth requesting?

There’s a number of courses I’m doing currently that I’d like ask the current maintainer about and/or make suggestions around, and would happily be added as a contributor if they’re no longer active. But from what I can see here virtually all requests to become contributors are being ignored?

I take it you’ve checked to see if any of the Creators have made it to the Forum.

PS [l also assume there isn’t a Forum Thread to the course already.]

If you’d like to post links to the courses, we, the Community, may be supporters (Contributors).

PS [Then the Contributor could consider your suggested amendments.]

Not every Contributor posts their name (ID) in the long description field.

It doesn’t get approved if the instructions aren’t followed exactly. They’re very careful about making sure a course really is abandoned and the creator can’t be contacted before they take action.
Also take into account that there is a lot going on right now at Memrise, and it may take a little longer than usual.