Yes. Like I said, the game is connected to the music, but the experience/playstyle is not as much, which is like you said, because it is not a rhythm game. That's all there is to it, I guess. The whole idea in essence would have been to allow a mode where it is more akin to a rhythm game.
It would indeed be a radical change to how the game is played (it could always be limited to a character/mode/whatever), but code-wise and score-wise it would not be a radical change. I was not aware of the [no-grey] tag, it pretty much does the same thing (I'd probably not have posted if I had known about it). The only difference in my original post was that there would still be grays in addition to that to avoid that were generated by something other than the music (they would be dissonant).
If you were to get into it more: It would be possible to base it on the mp3/file, but not the music it contains, so it would be the same track for a given song but the grays could be randomized, or it could be based on whatever else (backwards/reverse play of the track even, lol, any kind of strange filter could do too). I suppose it might also want to remove any grays that appeared too close in time to a colored block (though certain ways of generating grays would not place them badly to begin with).