what about the long answer? 
can you at least elaborate on that? as far as I know there are 2 things that can lead to thinking of a major renderer upgrade:
- Niagara. the entire thing needed some very deep rendering changes and as far as I know it pretty much led to a different rendering pipeline which is more flexible and efficient. this is from hearsay so I’m not really sure about it though, but if the rest of the rendering would be changed in the same way it could end up being a major renderer upgrade
- DXR/RTX. this one is obvious and of course this requires a pretty major upgrade to the renderer, however it doesn’t necessarily mean that the raster renderer would have any benefit from it at all, i.e. if non-RTX users will see any improvement
IIRC there was also some talk of other renderer changes scheduled to 4.22 and beyond but I don’t have a link to that