Make the next oculus rift as a VR that eliminates all the problems and imperfections on other VR. Combine every preferred features by users.
Most people prefer the old Rift CV1 design than the Rift S design. The major design flaw on the Rift S is a dealbreaker for some people. So i think, using the old design will be better. Just change some of the things for camera and etc. The Halo Strap design is an inconvenience and most people prefer the old Strap design like the one on the Rift CV1. Not the one on the Oculus Quest though i think. Put a nice pair of headphones on the Headset just like the Rift. People prefer the simple design just like the Rift. And not a bulky headset.
Just an idea but maybe you can do like a small compartment on the top of the headset to store the fiber cloth.
I don't know if this is suitable or not, but if it is, use a breathable sport mesh material as the VR Cover. I got the idea from Steelseries Arctis Series headphones as they use it for their headphone padding and it get a LOT of positive feedbacks on it as it is very breathable and comfortable. One of the drawback on the Valve Index is it is very hot when you use it (Based on Reviews). And maybe make it detachable instead of glued for hygiene purpose.
The Display needs to be 120Hz or something like that and the field of view needs to be wide. Because that's the main reason people buying the Valve Index.
Use the same design concept like the Index Controllers. floating on your hands. but maybe a simpler design than the Index controllers.
Make it Content creator friendly! Put an actual high quality mic on the headset. Maybe work with some professional mic brand? So content creators can just use the mic from the headset, without the need of an external lavalier microphone. Very useful for content creators who doesn't have one! Make sure to put in some important settings that they need though. (Gain, Compression, Noise reduction etc). And it's also useful for other consumers!
This is more to the software thing but put a useful settings for the built in headset for a better sound. Such as equalizer, Stereo Profile (this could help for the immersiveness of the VR as it will simulates listening to speakers in a large room.).
Make a high end VR with powerful specs but a simple look. Simple outside, Beast inside.
The following pictures is some idea for the upcoming Rift. maybe Rift Two?