I think that they should have the forest>fire>water themes they've done for most zelda games, and after the plot twist do things like ghosts or desert or ice. however I think they should change the actual dungeons to be real places. I really liked the goron mines and the snowpeak ruins, because they had a history, they weren't just mazes that happened to contain something magic. make the water temple be a sunken ship or flooded town. mabe a "lost city of the sheikiah" style dungeon o.o . keep the old themes, but get creative with them.