The screen quality is gonna get reduced greatly in the consumer model, that's a fact. They'll probably reduce it from 4K to 1440p. The refresh rate will stay 90hz since VR needs it so people don't get motion sick.
They might reduce the amount of cameras though that might make controlling it worse so they might not
Speaking of cameras, the quality of photos and videos taken from it will probably get reduced as well, saving the feature to the Vision Pro since it's the pro headset.
They could change the chip in it. Instead of an M series the consumer model uses the much slower A series instead, which would greatly reduce the functionality. Maybe even take out Mac mode on it.
Though I dunno about you but the thing I would want removed is that external display showing your eyes. It just looks weird. I get it, it's there so people can maintain eye contact while wearing the headset. But this is my avid VR user self talking that frankly I'd rather if people didn't see my eyes.