ISO is still a handy notation for light sensitivity and the "F" rating of a lens is the ratio between the lens's focal length and the aperture size. It would be nice if it was a linear arrangement, but nature tends to like a logarithm. Photography is mental math or, perhaps more appropriately, mental guesstimation when done on the fly. I'm lazy and typically use aperture mode because I know the depth of field I want in a given situation, and have it in my head what ISO I'll need for a rough shutter speed (for motorsports). ISO takes precedent in stills because I want the lowest ISO I can manage, in order to reduce noise.
There is still utility in the "old ways."