It's a matter of preference. Some people turn the chasse, others step directly to the side on 4&1 with no turn, waiting until the last possible moment to turn (which requires foot swivel). It depends on what you're after.
For social dancing, I think it's fine to relax the movement and open up prior to the forward rock on counts 2,3. Competitors generally won't, because it takes away from the speed and impact to telegraph the next movement ahead of time. (In fact, this is not a technique peculiar to the New York. Delaying the rotation until the last possible moment prior to the next step is common competitive Latin technique for many or most rotations).
It's interesting to note that the most current ISTD technique books actually split the difference. They want you to turn 1/8 between the "&" and the "1" count of the chasse, to end in open PP/CPP. Then another 1/8 between counts 1 and 2, to end in a side by side position. Of course, that, too, requires at least a little bit of swivel.
I had actually never heard of someone opposed to swiveling the foot on the end of count 1 into a New York. It's especially surprising to hear it from a seasoned competitive dancer. Are you sure you didn't misunderstand? If she actually meant just that, then is she recommending you turn 1/4 between the "&" and the "1" count prior? (The only other way to avoid swivel would be to step across yourself turned in).
As I said, there's nothing wrong with slow, relaxed rotation for social dancing. But I'm quite surprised to hear it recommended by a top competitive pro.
Regards,
Jonathan