I propose relaxed whole body breathing from the start. Simple.
In Goenka retreats there is three days of intensive Anapana focussing around the nose followed by 6 days of methodical "Vipassana" body scanning and one half day of Metta Bhavana practice.
I can not see how you can support the statement that "This is certainly not a big change from what I experienced while learning meditation from Goenka" - unless you did not follow the instructions at the Vipassana retreat?
Perhaps you could clarify your meaning for me as I'm truly a little confused.
I understand your question, but the answer is not straightforward black and white.
Throughout my time at Vipassana retreats, I would regularly use "relaxed whole body breathing" as you have described and taught it. It is sometimes useful at the start of the course, before ana-pana, to relax the body and mind before attempting to maintain focus at the nose/abdomen. When one gets to the 4th day, Vipassana is taught. For old students, full body breathing is encouraged whenever it is possible right from the start (they call it sweeping). Newer students work part by part in order to awaken the mind and become aware of more and more subtle sensations. At first the mind is unable to feel sensations all over the body, so
true full body breathing is not possible. But where it is possible, it is encouraged by teachers
in my experience! It is also encouraged after spending some time doing full body breathing to go back to working part-by-part, in order to ensure all parts of the body, no matter how small, are being awakened to the truth of anicca. Without doing this, there may be blanck or dull areas, and the mind remains gross - not subtle - to all of the teeny sensations all over, inside and outside of the body (anicca!). so why not work part by part? Without this, again -
true full body breathing is difficult or almost impossible for most humans who are very much caught up in their thoughts and memories, and have many dull, tense and blank parts on their bodies. Bhanga is a very helpful stepping stone in maintaining and learning to use full body breathing, and working part by part can help to reach that stage if "total dissolution".
Just being aware of anicca in gross sensations does not make the mind subtle. In order to make the mind subtle, one needs to look at all parts of the body, excluding nothing at all. If one moves from awareness of one gross sensation to another gross sensation, the mind remains gross. It is still helpful to be aware, but we are talking about *full body* awareness here, and full body breathing. And in order to do that, I personally think working part-by-part is a vital stepping stone.
Further on (Satipathanna 8-day course), awareness of mental contents is also taught. I find a little Mahasi Sayadaw style noting helps in this area, and has really boosted the awareness of mental contents as well as sensations (which is what you also teach). I think your
real issue with these courses is that they don't teach all of this stuff (full body breathing and awareness of thoughts) to new students from the very beginning, and also the "boot camp" style of the courses. And it's a fair point to make, but I guess the step-by-step thing works for some of us, maybe not others.
When it comes to following instructions, yes, I think it's important and it helps a lot... to a certain point. But as I've said before, you are your own teacher. Find out the truth for yourself, using your own experiential wisdom. There is something that is beyond words, or instructions, and when that rears it's head, then instructions are merely guidelines.
At the end of the day...
I maintain that Truth is a pathless land, and you cannot approach it by any path whatsoever, by any religion, by any sect. That is my point of view, and I adhere to that absolutely and unconditionally. Truth, being limitless, unconditioned, unapproachable by any path whatsoever, cannot be organised; nor should any organisation be formed to lead or coerce people along any particular path. If you first understand that, then you will see how impossible it is to organise a belief. A belief is purely an individual matter, and you cannot and must not organise it. If you do, it becomes dead, crystallised; it becomes a creed, a sect, a religion, to be imposed on others." Krishnamurti