During an interview for this year's Develop: Brighton conference, Todd Howard shared some more info on the eagerly awaited space RPG Starfield. The literally biggest news is the expected size of the map, which will be even larger than that of Fallout 76 (itself four times the size of Skyrim). Whether this refers to multiple surfaces or one big one is not clear.
In order to effectively create that much landmass, part of the map will be procedurally generated during development. According to Howard, procedural generation, which has been a tool in past games, is a good tool to create large landmasses quickly, but of course distinct landmarks are still handcrafted, which is standard practice for most open-world games nowadays. In Starfield and The Elder Scrolls VI, cities should become more lively both by being larger in size and by featuring more NPCs, who themselves will be playing a "larger role"—hopefully meaning they'll be more fun to interact with.
Howard also mentioned a planned overhaul to Bethesda's Creation engine, calling the improvements a "larger jump [in quality] than that from Morrowind to Oblivion." In particular, he named rendering, animation, and AI as areas where the most significant improvements have been made.
Starfield will be singleplayer-only, with no multiplayer component planned, and thanks to Microsoft's acquisition of Bethesda, both Starfield and TES: IV will be available on Game Pass from launch. You can watch the full interview above, which covers Todd Howard's career in detail, with the mentions of Starfield sprinkled throughout.