I was browsing the documentation and came across the "Experimental Features" section and clicked on it out of curiosity. To my horror I realized that the complete Open World technique, including things like grass rendering, are still marked as "experimental" since 2015.
I don't know about others here but I was under the impression that "Open World" is a firm part of Unreal and I for one am building a game on it. Lucky for me, I don't expect much to come from future Unreal versions for me feature-wise, so it would be no catastrophe for me to freeze on 4.20 (Haven't even installed 4.21 because there's nothing in there I could use) but srsly, Epic, this is a huge thing. Don't you think you should invest some resources in this bread-and-butter technology to mark it as stable?