I've been involved in a few space planning projects now, and it always seems that we are surprised at how we look when we see ourselves reflected back through the eyes of outsiders we've invited. Architects and other outside consultants can offer a view that we can't get from our own entrenched positions and that is a good thing.
Outsiders only know what you tell them and what they can see. When you see yourself through their eyes, you can get a good look at the foundational narratives of your organization: the stories you tell yourselves. These can be good or bad, but they are foundational in a way that makes them hard to uncover during day to day business. When what they see and what they hear don't align, that gets drawn out in discussions and narratives. You find yourself being asked to clarify why things that conflict with your narratives exist.
Outsiders don't have a vested interest in the organization. They can't retaliate directly against anyone, and can anonymize issues. If you let folks talk directly to the architects, consultants, etc, either individually or in peer groups, you can get feedback that might never get spoken aloud in other contexts.
A colleague of mine recently invited an "equity consultant" to come and work with their department. The consultant held a day of open forums for undergraduates, graduates, untenured tenure track faculty, adjunct faculty, women, faculty of color. The forums were open to those groups specifically, and afterwards he reported back what he had heard to the administrators and leaders in the department. The result was a deconstruction of the narrative of "we've got a few issues but we're doing okay" based on hearing comments that people only felt comfortable making in a safe space.
Even when a consultant isn't hired specifically to address issues like "are we a truly equitable workplace" or "what are our foundational narratives," when you pay attention to the organizational dynamics that go on when an outsider is involved (especially for an extended period like with an architect), you can learn a lot about your organization. And, most importantly, you can use that information to start to make changes to be a better organization.