So I realize that the FFE never had a Blind Spot Monitor available, but I'm thinking ahead to the Mach E and other EVs that Ford is working on here.
Besides my Focus, our other car is a Mazda CX-5. When there is a car in your blind spot and you use the turn signal for that side, a chime sounds in addition to the little light on the mirror flashing. After renting a Fusion, I discovered that Ford does not even give you the option of having the car make a chime when it might not be safe to change lanes. On the Mazda, you can turn it off if you find it annoying.
This seems ridiculous to me, as I personally find the chime to be the most useful part of the system, making it possible for me in heavy traffic to focus on the car in front of me while instantly knowing whether I should even bother to look over my shoulder to verify if the next lane is clear. It would be such a simple software fix, I'm hoping they can add it to the Mach E before it goes on sale.