What would a "rando-specific geometry" be, or what would be the key characteristics?
Well, when I think of a rando bike I think of classic French style geometry, which for the most part just means a moderate (73 or so) head angle with lots of rake, like 60mm. With wide tires, this results in a bike that is stable at lower speeds without being tank-like. In truth, about the only difference between that geometry and the typical modern geometry is the fork rake: modern bikes tend to come with 40-45mm of rake, which works fine with narrow tires and higher speeds (like 20 to 60 MPH), but not so well with wider tires and lower speeds (like 15-20 MPH.)