There is so much lore in the world of Botw that weren't really explained or said in the main story. This is so exciting to know they worked closely with the Zelda team and this was Aonuma's idea to make this game. So i'm sure it means they wanted to give out more story, which i think is a good sign for the sequel since maybe they learned from their mistakes of just going on the surface with Botw.
But yea, i'm expecting something more story focused and of big quality. They will def give more background or else there would be no point of Zelda team getting so involved. Zelda Botw 2 should be late spring 2021 at best now.