Yeah, that's all reasonable.

But why wouldn't we go the other way and say "getting a user directory for a different user is not supported and all existing ways to do it are now deprecated"?

I know you think that's not a relevant argument right now, but it is a related one, and any change to the status quo justifies bringing it back up. So now it's up, we want to decide on it before we make another change that could run counter to the overall direction.

So I think, given the unlikelihood of us being able to properly fix the functionality, that we should deprecate getting another user's directory completely and, hence, not add new entry points to deprecated API.

Convince me I'm wrong :)