I enjoyed the planetary exploration in No Man’s Sky. Some planets have an outpost, but most don’t. In No Man’s Sky there are several alien races and artifacts they left behind you can learn their language from.
There are a huge number of planets, and some have strange reality altering properties. They have different weather and conditions. There is a ginormous amount of alien life that you can catalogue and interact with and even tame. The planets themselves show a huge variety of differences. There is even underground and underwater environments with unique life suited to those environments.
The base building is fun. You can do a lot and you can even travel to galactic hubs and worlds that other players have worked on.
Even travelling through space is more fun. You are able to fly to planets and land on them seamlessly. You can own several different space ships and even giant freighters that can contain your ships and frigates you can send to other star systems.
I think it was about all of the above. The actual quote is about the game size, but not all the way. He says that smaller studios may not have the resources to do what they did by having a multi-year early access period. Remember, they have to pay people that whole time without getting much money from the product. Also, he points out that larger studios such as the one making Starfield should have the resources to do what they did and more.