I've seen the presentation of Nanite and Lumen a month ago and they seem like very interesting technologies. I still haven't seen a game implement Nanite to get a significant performance boost though. Lumen is more of a filmmakers tool, since lighting in games is often preferred to be more stylized than realistic. But this also brings up another issue with UE. The constant updates distract developers from actually fulfilling their vision and finishing the game. Early Access titles often stagnate development to update to a new engine version and implement new technologies, instead of providing content and bugfixes. And if you don't update the to a new engine, the community whines about it. So the devs have no choice. The versitality has its price, it's like UE tries to become jack of all trades, but master of none in an effort to provide everybody with a platform.