As a matter of fact, Reference 3a speakers need to fire directly into the room. Anything more than a minute amount of toe in ruins the tonal balance. And this is by design.
So even though soundstage depth may be enhanced by severe toe in, many other parameters may suffer. This is an individual listener and speaker preference.
Good observation and needs to be emphasized, much ’depends’ on the specific speaker in question and the room/speaker relationship. Generalizations aren’t applicable in this type of scenario. Case by case approach is the way to proceed. Good topic!
Charles