Again, the insistence on a "code" with the implication that it will last for all time.
Someone observed further up that these Elves expect to live forever barring unfortunate incident, and even that would only be a pause. Why would they want to bind themselves and all of their descendants to a decision made here and now with no knowledge of later developments?
Establishing a rigid code is entirely too much like human thinking for immortal Elves: mortal people who lay down a code now are hoping to impose their will on people yet to be born. Elves expect to be there to argue their side, they won't need a code.
The arguments being made against a succession plan are not consistent.
On the one hand there is the argument, Elves hope the one High King will never die and reign forever. So they are hoping for one monarch to rule them for all eternity according to some, then at the same time they don't want to bide themselves to any codes that may last forever.
How is establishing a code (a rigid code is exactly the opposite of what I have argued) imposing their will on people yet to be born, but Ingwe ruling the Vanyar for all time not so?
If any group hates change and wants things to remain the same, it's the elves. Sauron manages to ensnare them, because they want to stop time.
The chief power (of all the rings alike) was the prevention or slowing of decay (i.e. 'change' viewed as a regrettable thing), the preservation of what is desired or loved, or its semblance – this is more or less an Elvish motive.
Freezing time and keeping things as they are is EXACTLY how Elves think.
Look at what Finrod has to say.
'Can you deny it? Now we Eldar do not deny that ye love Arda and all that is therein (in so far as ye are free from the Shadow) maybe even as greatly as do we. Yet otherwise. Each of our kindreds perceives Arda differently, and appraises its beauties in different mode and degree. How shall I say it? To me the difference seems like that between one who visits a strange country, and abides there a while (but need not), and one who has lived in that land always (and must). To the former all things that he sees are new and strange, and in that degree lovable. To the other all things are familiar, the only things that are, his own, and in that degree precious.'
According to Tolkien the desire for constant change is a Mannish quality, which the elves don't. The elves generally with the exception of the Noldor in Valinor are content with their lives and DONT want thing to change.
Look at Galadriel's wish.
'Yet I could wish, were it of any avail, that the One Ring had never been wrought, or had remained for ever lost.'
She fears a time when time will come and change her land.
'Yet if you succeed, then our power is diminished and Lothlorien will fade, and the tides of Time will sweep it away.'
In my opinion the truth is completely the opposite of what you have said. It's a very modern philosophy to want constant change and progress. You are imposing your modern viewpoint on the elves, which is not backed up by the text or even human experience. In the text I can give numerous examples of how immortal or long lived creatures are resistant to change and like to freeze time (Ents and Elves). This goes back of course to Eru, who is eternal and unchangeable. Even in general life the older one gets the more resistant to change and conservative they are. I can't think of anything in the text to back up your reasoning.
Secondly, I never ever argued for a rigid code. In fact I have constantly, argued for the opposite. I have compared it to the British Constitution, which is easy to change, not written down and always adapting. I have compared it to an organic tree. I have repeatedly argued for a fluid ideas of succession being laid down and developing over time, with the princes arguing over what previous decisions meant.
I believe we have to fight the subconscious desire to make elves and the Noldor in particular, like ourselves or a perfect version of ourselves. The Noldor were not perfect by any means, in fact they are the most flawed out of all the Eldar and they are not like our modern society.
If the Noldor were randomly electing Fingolfin as High King first then Curufin, followd by Maedhros and then Glorfindel, followed by Gwindor before going back to Fingon, then you would have an argument there was no order.
However, we see a clear pattern in the High Kings.
1. All are descendants of Finwe
2. All are male.
3. The succession seems to follow Salic Law.
The line of High Kings implies order and not chaos. I repeat I have never once, argued that the Noldor had a clear code or plans when Fingolfin was chosen. They would argue over who should be the next king and the criteria for choosing the next king. Certain ideas would be added and other ideas would be rejected. For example the question of whether the Feanorians were barred from the throne would come up in heated debate twice. First at the succession of Fingon. Did Maedhros just set aside his claim for Fingolfin (the oldest of the Noldor princes) or for the entire House of Fingolfin. Would Maedhros want to press his claim as the oldest living prince over his good friend Fingon? Did Maedhros not push as hard as possible, because Fingon saved his life? Did Fingon win, because he was just more popular than Maedhros. Once Fingon is declared king it will be decided that the House of Fingolfin comes before the Feanorian claim. The fact that Fingon only accepted this, because Fingon saved his life will not matter. It will set the precedent that the House of Fingolfin comes first and confirm Turgon as the next High King.
Then again at the succession of Gil-galad. It was decided that Maedhros' claim would come after the House of Fingolfin, but should it be behind the House of Finarfin and to a younger elf not even born in Valinor? Maedhros and the Feanorians will strongly press their claim, but of course the decision will be that they are barred from the succession. If there hadn't been a Second Kinslaying, if the Fifth Battle had gone differently then maybe Maedhros would have been High King, but it didn't.
These decisions would not be from Unchangeable Codes, written in stone by the Noldor as soon as Finwe became king, but instead set precedents that need to be followed to keep order, unity and legality.
EDIT
I will even go as far as saying if the weakness of Men, is to wish for immortality and to escape death, then the weakness of the elves was to stop change and wish for stagnation.
This becomes a great burden as the ages lengthen, especially in a world in which there is malice and destruction (I have left out the mythological form which Malice or the Fall of the Angels takes in this fable). Mere change as such is not represented as 'evil': it is the unfolding of the story and to refuse this is of course against the design of God. But the Elvish weakness is in these terms naturally to regret the past, and to become unwilling to face change: as if a man were to hate a very long book still going on, and wished to settle down in a favourite chapter. Hence they fell in a measure to Sauron's deceits: they desired some 'power' over things as they are (which is quite distinct from an), to make their particular will to preservation effective: to arrest change, and keep things always fresh and fair.