not just for pinpointing the difficulties, but especially for understating why is there this passage, what's its role in the whole structure (that usually helps me build an image on how it should finally sound, so, there, i have an aim for this particular passage)
Now, now Anda, you cannot resist disagreeing with me can you? (and you promised!)

First of all, have you read the full thread? It is not about learning a new piece. It is about developing technique from a piece. This was actually one of my very first posts.
The answers people gave were: “Play it!”, or “Practise it!”. And other very helpful stuff like that. So the list you decided to comment on is by no means complete. It was meant as an example of the sort of thing I was expecting as an answer.
So let us have a look at your additions, shall we?
not just for pinpointing the difficulties, but especially for understating why is there this passage, what's its role in the whole structure (that usually helps me build an image on how it should finally sound, so, there, i have an aim for this particular passage)
Certainly understanding what is behind of a piece of music is of the utmost importance for its eventual performance. It is of almost no importance if you are working on a particular difficult physical movement. If you have to give an accurate skip or if you have to do an awkward change of fingering, analysis is not going to help you. You just will have to work on it on its own (physical) terms.
But perhaps most importantly, I would certainly not analyse a piece when sight reading it. I would do that by referring to the score, miles away from the piano. Is it important to analyse a piece? Absolutely. In fact I will not touch the piano before I have the piece thoroughly analysed in terms of motif variations and development, harmonic structure and form and so on. Will I do that by sight-reading the piece? You must be joking.
So the first sight reading will show me instantly how well the piece falls under my fingers. Have you ever got a piece that looks easy on the page, and yet as you sight read throught it your fingers tie themselves in knots? So this is what I am exploring when sight-reading the piece.
Am I developing technique form the piece at this stage? Of course not. I am investigating the areas that will need technical work.
the passage usually comes from something and continues with something, so the passage to practice starts before the bars with problems and ends after. the passage to practice is usually a motif/phrase/period. practice technically to get all notes clear and keep in mind all the time the image you decided on.
Yes, I could not agree more. That is in fact what I said. But sometimes a motif/phrase/period cannot be tackled in its entirety. Sometimes a whole passage is falling apart because of only two notes. If so you must ignore for the moment the larger episode and work on those single two notes until you master them. The alternative is to keep practising the whole passage and playing it badly because either you are unaware that the two notes are causing the whole problem, or from simple laziness. The consequence? Soon that tiny technical problem will have developed into an ingrained habit and you will have to sell your soul to the devil to get rid of it.
personally, i hardly ever practice separately: i would practice separately a jump, or a fast passage in abnormal sequences (and that usually takes only a gew minutes). i agree on the importance of fingering, once you found your own best fingering, the devil isn't that black anymore. also, on this stage: for every passage decide which hand has to play without visual control and focus on the other.
Of course you never practise hands separately. You are a concert pianist, for crying out loud! At your level I doubt if you have any technical problems (in the sense of physical movement) left to solve. So, yes, go straight to hands together and my bet is that even co-ordination (which is what one learns when practising hands together) is not a problem for you. So of course, you should waste no time on this and you should indeed move on to voicing and interpretation.
But for a beginner/intermediate player it is important to understand that it is not possible to acquire technique and co-ordination at the same time – or let us say that it is possible but much more difficult and time consuming. So for a beginner –intermediate student, separate hands
for the passages that they find technically challenging – and only for those passages it is a must.
Consequence of not doing this: As the student plays, s/he always botches the very same passage. No matter how much they practice, that passage is a major block. Continue doing this with hands together, and soon it will be inbuilt in hand memory. And continue doing it for some time and to the physical problem you will add a psychological problem that will hinder the student even if s/he conquers the physical one (“oh, no! there comes that passage I always botch!). Avoid all this suffering at the root by practising technically challenging passages (for the student, not for you) with hands separate until the passage becomes easy as a breeze. Then join hands.
And yes, that is one of the beauties of hands separate practice: it only takes a few minutes – even for beginners – to master the passage.
By the way, it is not necessary to practise the whole piece hands separate. Just the technically challenging bits (but a total beginner may need to do the whole piece with HS).
Again, this is advice for developping technique from a piece. It is not advice for, say, learning to sight-read. If your goal is to learn to sight-read, then hands together is a must.
this is something i never do. especially rhythmic variations... i totally forbid my students to practice in different rhythms, i found it ruins their rhythmic sense. i prefer working on the passage exactly as it is written (rhythm, dynamics, everything), also helps the hand memorizing.
Of course you never do. As I said you probably do not need to do it. You already have a superb technique.
The advice given is for someone who has reached a dead end: They practise (usually this means that they unintelligently repeat) and do not get anywhere. I have never seen anyone’s rhythmic sense being destroyed by rhythmic variations. Quite the opposite, it sharpens it. And if you look at any composition, what is the composer doing (amongst other things) but rhythmical variations on a motif?
Rhythmical variations in particular are not a general practice procedure, but they will be particularly helpful in fast, even, running passages (e.g. Schubert’s Impromptu op. 90 no. 2, or variation 1 in Mozart’s “Ah Je vous dirais maman”).
By the way, forbidding students to do something, just means they are going to do it behind your back he he he

. How many of your students do you think are members of this forum ands getting ideas from me to do what you forbid them? He he he

especially when you're dealing with more than 2 voices, i always practice (and have my students do it as well) on combinations of voices (1+2, 1+3, 2+3, or, if there are 4 voices, all combinations of 2 and 3 voices), always with the final fingering and always with the correct dynamics and everything. helps the ear get used to different levels of sonority. also, memorizing should have happened long before reaching this stage.
No, memorising has to start at the level where everything is simple: when you are dealing with a single voice. Are you suggesting that one should memorise a whole Fugue and only then take it apart?
Quite the opposite. Start with one single voice and memorise it. Then do the next voice and so on. Then join them in parts (as you said: 1+2, 1+3, 1+4, 2+3, 2+4, 1+2+3, 1+2+4, 1+3+4, 2+3+4, 1+2+3+4)
But then again, this is about memorising, not about developing technique from a piece.
In fact, if the purpose is to thouroughly learn a fugue, a very good strategy is to reverse the voices, since this more than anything else will teach one to think contrapuntually. But this will not help you with technique: It assumes that you already have the technique.
yes, bother! i had a teacher once who used to say that the sound (the quality of the sound) is a technical problem! even if the passage doesn't look technically chalenging in the begining, based on personal experience i can tell you that in the end, these are the passages that eat you inside out, and especially for us, who have to play on different instruments wherever we go, these passages get to cause you most trouble.
You are not reading carefully, Anda.
Here is what I said: Do not bother [practising separate hands] the parts of the piece you have no technical difficulty [meaning: go straight to hands together practice on these passages]. Since you yourself said you never bother practising hands separate unless it is a difficult technical passage for you, why are you now stating that you should bother?
Of course quality of sound is technical, but I was –for the purposes of discussion – restricting technique to physical movement. Of course everything is interrelated. Of course this all goes without saying.
sorry, i have to disagree with you on this point - you cannot separate technical issues from musical ones. the best way (and believe me, i tried on myself doing as you say, i have had teachers who practice this theory) is to work on all levels at the same time. it may seem like too many things to worry about at the same time, but in the end you'll find it saves a lot of time. also, you get to skip the part "find out you need to modify your technique if it proves inadequate for concept"
Yes, I agree that technique cannot separated from musicality. However, for
learning purposes separate them one must. Piano playing is a complex task. Not a
complicated task, but a complex one. As such the way to learn it is the way one learns any complex task: break the task into its simplest components. Practise each component so that its performance becomes unconscious. Eventually all the single tasks will “gell” into the complex task. This “gelling” happens by itself and it is a most mysterious process an at the moment of writing not understood at all (ask any psychologist). However, just because we have no idea how it happens does not mean that it does not happen. It does, and the best (perhaps the only) way to make sure it happens is to keep working at the separate components.
Of course, if you are an advanced student, or in your case an accomplished pianist, many of these simple components will already have been fully mastered: they are part of your unconscious. So you can give yourself the luxury of approaching a piece in a “holistic” manner. Good for you!
However, beginner/intermediate students will be completely lost with this sort of approach. It has been tried by well meaning pedagogues in several areas. It was a monumental failure. Faulty Damper has described one such pedagogical initiative and what happened to the students as a consequence. I suggest you read it:
https://www.pianoforum.net/cgi-bin/yabb/YaBB.cgi?board=teac;action=display;num=1081684084;start=1(it is the second post on the thread. Read the second paragraph wehre he talks about what happened in Californian schools)
Best wishes,
Bernhard.