Very few of the 4.0 houses have interiours sadly. I liked being able to enter various shops/residential areas and see how the people lived in them. Be it from Tailfeather to the Silver Bazaar, most of the houses have actual insides.

I was especially sad that none of the doors in the Ala Mhigan residential area could open. If any of the places in the world would be great for such secrets/hidden stuff, that would be it :/