It's easy to redefine the meaning of a term if it's rendered as an acronym.
User Interface Designer = "white space"
User Experience Designer = "mental space"
Now how arbitrary is that? What is it about "Experience" that implies thinking and "Interface" that implies a lack thereof? What about all the designers unfortunate enough to come before the term "UX" was invented? I suppose Jef Raskin was only ever about white space.Let me suggest an improvement
Mediocre Designer = "white space"
Good Designer = "white space and mental space"