There are already many ways to edit to a beat very quickly in AE. Also when you say that audio to keyframes or Trapcode sound keys is not suitable to this you are missing a tremendous amount of functionality on both of those effects. If I need to do what you are describing, many many cuts to a beat in a short amount of time, I will timeout the distance between the beats, set in and out points for however many layers I want to cut lining be in point up with the first part of the beat, the outpoint with the start of the next beat, and then use the keyframe assistant to sequence the layers. It takes just a few seconds to put 100 cuts in sync with an eighth note.
I have been cutting to music for more than 40 years and quick cuts in sync to a rhythm track is always easy if you don't try to look at each beat as a separate event. Back in the film days I seldom if ever marked every beat with the wax pencil them painstakingly matched up little pieces of film. Instead I would put a mark on the editing table 4, or six, or 7 1/4 inches long, then lay out my little pieces of film and trim them and splice them together. Took minutes not hours.
I'm not saying that a tempo grid overlay on the timeline would not be a useful feature, I'm saying there are much better ways to use the existing toolset.