Start Citizen 2: The Andromeda Galaxy.
A true dream sequel, keep on dreaming!
My Dream sequel would be a Team ICO game made for PSVR 2.0 with all that made ICO, SotC and TLG great.
GTA 6 based on photogrammetry data. Take something like blackshark AI (used for FS2020) to work on all major cities that have photogrammetry data available (3D cities on Google maps) to clean it up and make procedurally generated real cities. Choose your city to play in and all the stories and missions will be procedurally placed inside the chosen city based on meta data for each city (where/what everything is) This is all prepared in the cloud. While playing you stream data from the cloud like FS2020 or pre-download the city you want to play in.