but I don't think it is as nice.
If you look at that Simula VR page there is a video showing a person working with the device at a coffeeshop and being handed a coffee by a waitress. I don't know what that waitress would think about the interaction, particularly she might not be so clear if the person wearing the headset is paying attention or not. Visible eyes on the outside of the device could make a big difference. I don't think you'd need a particularly high quality display for the outside, something cartoony might be good enough or even better than a realistic display.
Like a matrix display...
The pro could increase the FOV (some mentioned black borders at edge of vision), increase refresh rate and brightness (some mentioned adjusting to room brightness when removed), reduce the weight and thickness with titanium (some mentioned unbalanced weight), have more private sound (I understand it is pretty noisy to the neighbors so you would currently need AirPod Pro for plane/bed use), increase the cooling system (some mentioned it is warm), get some sort of med-tech sensors (control with thoughts, detect stress etc), get back sensors (the AirPod demo of being passed by the bike seems it needs some sort of backup camera/360 video record options), get cellular features, get Mx Pro chip, and increase the front screen size. After that I expect outdoor waterproof Ultra models (The scenes of people twitching on couches compared to the iPod dancers flinging themselves around could not be more stark).
Many reviewers also mentioned getting their hair messed up making it unwanted in professional scenarios where sharp looks are important which is something to solve for a true pro model. I imagine corporate will want all sorts of usage data and screen sharing.
It helps to think about the “SE” models of iPhone and Apple Watch in relation to this. And it will have its own target customer base for which it makes more sense than the Pro.
By the time it comes out the pro model will move to the M3 or M4. Storage will also be lower on the non-pro model, and you wont get the same level of sound quality (Which for 99% of people wont matter as they'll have Airpods being existing Apple users).
Apples historically launched pro products, and then when its ready for a performance and/or feature bump it's passed those old features down to the non-pro models. Think TouchID and FaceID for example.
If they swap metal for plastic, the cheaper version would become lighter and that would be a selling point. They can't go with lower-resolution screens. Poorer quality headband would make the thing uncomfortable to wear.
It's hard to believe that the screen on the outside is really necessary, but I'm sure it did well in testing or it wouldn't have been included.