Takahashi basically said XBX was a focus on making an open MMO world first, game/story second and that the next game will have much more story focus/meat on it.
The world was fantastic, I agree. Gorgeous and great music. Cool to explore....on foot. The on foot battle system was also great and an improvement over Xenoblade's battle system. But while mechs are cool in games and it was awesome to first start driving/flying, mechs basically made transitioning through the world a joke and the mech battle system was incredibly broken and sucked. The sidequests were mostly bad MMO fetch questing with the occasional good one and the main story quests/progression were pretty bad. Plus the whole lack of real developed characters and a plot.
If Takahashi & team make more cool open worlds, but this time add characters/plot and meaningful content (and balance the mechs more) then it'd be great. I have a feeling XB2 is going back to semi-open world though in the XB style of linear world zones with big open maps so they can focus on storytelling and get the game out fast. I've heard rumors that it may be a short <2 year development ~30-40 hour linear stopgap game they're doing for Switch's launch before getting back to a 3-4 year developement big open world game with XBX2. That being said, even a smaller, shorter and more tight Xenoblade-style XB2 will be good as long as the story & characters are good.