Personally, I'm not for a million af points on the screen. I want a nice selection I can use different zone settings, covering much of the area as possible.. but I don't need hundreds. Love to see where I could select MY wanted AF points, in any combo, and then roll thru them on a dial. Like my own custom AF layout. THAT would be exceptional and fast. There are times I need the camera to do all the af for me, but many times I know where I want that point of focus at. Most of the time I don't need or want a zillion, and they get in the way when there are too many.. being able to select a sub set, and roll thru them is my ideal camera.
The Sony's have such a high number of AF points because the AF points span the entire frame, and because they provide a greater density of AF points when tracking, and thus, are able to make smaller, more precise movements when tracking.
That said, in real use, you're usually designating AF zones or movable AF points that you can toggle to different sizes. A small point is limited to 1 PDAF point, medium is a cluster of points, and large is a larger cluster of points. Personally since I shoot primarily portraiture, I don't mess with AF points at all and rely primarily on continuous eye focus and face detect. When not shooting portraiture, I use lock-on focus to acquire the subject via the center-point....and let the AF system lock onto my subject as I frame the shot. As these AF systems grow ever more intelligent, toggling through AF points is growing ever more antiquated.