This is a bit tricky - what exactly is the V5 ?
To go back in history, as far as I can recall (there is a lengthy Pimax post from early 2018 where they recapitulated the history, too lazy to search for it now), V1 will have been the prototype shown during CES 2017, then in summer the KS campaign roadshow utilized V2, V3 being announced to hit the US shows towards the end of the KS campaign, but it saw delays and I believe it was only shown in NYC (?). V4 has never been shown in public, V5 was then featured at CES 2018.
Since then it seems that they have undergone 3 substantial retoolings for the lenses, yet they still seem to refer to the prototype as V5. But, perhaps all of the current activities actually do not affect the V5 prototype, but are only (failed) try-outs to establish the M1. So the V5 could in principle still be the same faulty piece of hardware shown in January - but you can bet that they did apply some fixes, surely for the tracking issues which likely came down only to the material chosen to cover the sensors. If this were true, it would mean that all of the videos shown with V5 actually use the lenses prior to the 3 failed M1 tooling attempts.
But what does the above assumption mean for the lenses ? If the V5 does not use mass production lenses yet, they should have been as good as the V2/3 lenses, i.e. with a sweet spot reaching almost to the rim of the lenses. However, the latest videos seem to suggest that the sweet spot has narrowed quite dramatically - in that case it would appear that they have actually shot the videos through the newer inbetween V5 / M1 prototypes. If that is the case, I just hope they can get the lenses back to a sweet spot as shown with V2, and they would be absolutely correct in assessing that they better do not release the 8K with such dramatic reduction in performance of the lenses. I accept that the mass production lenses may not be exactly as good as the V2 lenses, but if they go back to a sweet spot comparable to the Rift the 8K would have lost one of the major improvements it provides over the 1st generation of VR goggles. That would be quite disappointing.
After having tried it out, I expect from the Pimax 8K the following substantial improvements above the Rift/Vive level:
- greater resolution
- greater FoV
- lesser/no SDE
- greater sweet spot (covering almost the entire visible area)
That is a pretty short list. But all of these are important, primary qualities of a VR HMD. If one of them goes back to 1st gen level, it will be a blow. It would not mean that the HMD is useless, but it would diminish its significance to a certain degree.