I have to stick my neck on the line and voice my opinion that the rotating for some players may actually be a 'sweet spot' or 'sweet grip' thing. Although I doubt that players, (including myself) do this in order to find sweet playing spot, it's more or less finding that sweet feel spot. Last night I watched a play doing this, and I watched him rotate the cue on every shot, and each time, without appearing to be looking, he came up every time with the same rotation when he would finally pull the trigger. This was easy to see because there was a highly visible scuff mark on his butt cap, and every time he pulled the trigger, the mark was in in the same position.
As for me, I replaced my ferrule with a buckhorn ferrule about a week ago. My ferrule has a distinct dark side and light side. Last night as I played, I remember seeing the dark side of the ferrule as I was about the pull the trigger. Now I remember specifically that on that particular shot, I felt almost as if I had pulled the trigger too quickly, and that something was wrong with my stance, alignment or something, and come to think of it......................as far as I can tell, that is the first time I can remember seeing the dark side of my ferrule as I stroked????
I've always believed that muscle memory has a very high level of potential and consistency, and I think that for some, the rotating of the cue during warm up strokes is the way of settling into that grip that only the body can know and 'feel'. And based on what I saw last night, that grip for many players is generally on the same radial axis.
dave