To add to that, another museum could be built as well, perhaps at the south end of Museum station, so that Toronto would have its own version of NYC's Museum Mile.To build off of AoD's suggestion, I've always liked the idea of closing at least the west side of Queen's Park Crescent to reconnect Queen's Park and the U of T campus. Recreate Taddle Creek through the area and create a large park through downtown (partially on U of T's campus but few would see the difference). I've never considered burying the entirety of Queen's Park Crescent because it struck me as unnecessarily expensive (because of the University line) but if it were doable it would certainly make closing the road far more palatable than my idea (to make the east side of QPS into a two-way road lol)
The ROM could be repurposed to be either a natural history museum (like the American Museum of Natural History) or an anthropological art museum (like the Metropolitan Museum of Art), while the new museum would focus on what the ROM would no longer focus on.
The ROM stated that it has an undisplayed collection large enough for a second museum the size of the ROM itself.