All of these are good points. And I agree with them, Improvisation has unfortunately died out in classical music in favour of strict score accuracy.
There really are only so many ways you can play the exact same piece of music.
The question is certainly up for debate we we ask generally how important urtext editions are in general, but as mentioned, in terms of studying for competitions, as they currently are, these editions are still the most accurate and most important.
One thing I wonder, on the basis of Chopin's argument of playing it differently, why did he feel the need to add so many dynamics and phrasing, when we could have left this up to the performer to decide for themselves? He remained very consistent with his style of notation, and when you see the scribbling out on the original manuscripts, it's clear he had a specific set of notes that were to be put on the page, not up for debate.
Possibly one statement isn't enough for us to know how he really felt.