To be honest when the subscription feature with the option to feature a title came out I thought that a lot of people might pay for it, but it seems like since it was a fairly expensive support tier that didn't happen. I think it would be pretty common if it was slightly less expensive but I also think it would end up with a lot of people wanting an option to filter out featured titles if what gets featured isn't to their taste.
I saw another thread suggesting a "similar to this title" feature which might be more useful. I was thinking a user submitted "if you like this, you might like that" feature similar to MAL might be useful, or for minimum coding, an option to automatically create a thread in the discussion for a given manga that's "Recommendations for fans of this manga" or something.