I feel if this actually got off the ground he’d inevitably reconstruct his 4 hour cut as it was before Fox went in and did their own thing. Cuz as we know they pushed him around on set but he did what he could in the editing room before the top dogs went “nope.” I don’t think anything SFX would get changed really. Lynch isn’t super into that sort of thing to be honest.
Whilst I agree with your sentiments the fact of the matter is let’s take for instance I think it’s the 6th Draft after the Jamis fight. The Fremen with paul and Jessica set out from the rocks at dawn and go to “Sietch Tabar” chani points whilst they walk in the desert and says (sorry if there is spelling mistake) “Sietch Tabar” So this relies on having an image of this place which they may or may not have filmed. Although you could say ok don’t include the scene because we don’t have the fantastical location that does not exist. Of course it can be remedied by creating it. These sorts of films are like chicken and the egg. You can argue all day which one came first but the reality is that the egg needs the chicken just as much as the chicken needs the egg.
A Special effects film needs special effects constantly and consistantly especially one like Dune with blue eyes roto in on loads of shots but the actors and the performances are just as important. The World is important and that is something Dune did tremendously well with it’s production design.
I think the amount of work it probably would requite is daunting but at the same time it makes it much more plausible that people would want to have a go because it would be a challenge and that makes it more credible. A challenge is something that people can get behind.