In the age of programmable shaders - and even before that with fast CPUs - it's not about a single feature, in general terms, in isolation, being what determines "next gen". "Next gen" is a about the totality of what hardware allows, or that a new API allows to be accessed in newer hardware. Oh, and it's also about the asset pipeline as making use of features can often require assets (particularly materials) to be built or tuned for them.
"Next gen" is subjective, and in the hands of some almost arbitrary. For me it's probably when a game lands on new(ish) hardware that's giving results, and large scale employing expensive techniques, that are clearly above what "current gen" could do. That's open for debate, but I think CP2077 could well be such a game on the right hardware. The RT lighting is well beyond PS4 and X1, GCN and Maxwell.
Maybe for you it's about someone coining a phrase for a technique that you've not heard before, or a game not having a last gen version even if it could be done, or ... whatever. But if you're going to post compulsively in this topic talking down ideas about what makes something "next gen" for others, you need to be prepared to say what you think would make something "next gen". And not in vague terms. Be prepared to actually define it, and give specifics when asked.
You might be surprised just how many techniques could actually be pulled off - in some capacity - on old hardware.
