> The cases where _user is required, and a user data / ID view is used, far outnumber the cases where it is optional.

This is probably true. The reason I raised this up is that in leaderboard, the `_user` parameter is optional too (specifying it only show the user`s friends) I think having a field to mark _user as optional is a good compromise.

> user doesn't even seem to be used in this endpoint anyways...
I think this is still WIP. The pull request stated that if the `_user` param is specified, the user info will be added to the feedback data. I'm guessing that using userIDView would be more appropriate in this case