Ok Let's Gofags, before they start saying: "We were right, the random encounters are part of the past, blah blah blah" ... No!, Sword and Shield will not be exactly the same as Let's Go, because you will see in the 2 first images, there will be traditional routes where random encounters will continue to exist, and as seen in the below ones, the overworld encounter will be something exclusive to the Wild Area.
So we could say that Game Freak has chosen to please the two types of public, the new and the old, created a hybrid system where random encounters and viewed from the outside coexist to maintain the essence of the main saga, watching the trailer carefully, it may be that there are pokemon that are seen above, but when walking the grass there is still the possibility of you skipping a random encounter, so neither one nor the other, is what some asked, a hybrid between the two.
So do not worry, the shinies will not be devalued, you can still do nuzlockes in a traditional way, and not every encounter can be dodged like in Let's Go Shit... I as a biggest detractor of the OW Encounters, one of the things I thought about that this mechanic would not fit in the main saga, is that it was not open in maps enough to merit it, but I see that there will be areas that do need this mechanics to give life to the environment, and more closed areas where the random encounter will remain something vital for the random and wear factor.