Retuning existing recorded music from 440 to 432 is not going to change anything beyond making it momentarily sound flat when played after hearing 440 tuned music as all harmonic relationships will remain unchanged.
Retuning an acoustic instrument with a fixed resonant body will however make a difference as now the strings will be resonating at a slightly lower frequency relative to the natural resonance of the instruments body and the result may well work better for some tracks and less so for others. Some note will sound thicker while other maybe a little thinner depending their excitation of the instruments body.
In my DAW, I can load up a track and change its speed and pitch independently, so if I want to, I can already do this. IU have an application called melodyne that I have used for a along time for retuning samples, vocals and even re-keying chords in samples.
While modern pitch change algorithms (that preserve tempo) have got very good, they still tend tend to leave unpleasant artifacts which some of us used to working with these algorithms most definitely notice and usually when such are pointed out to others, they tend to notice them as well.
Part of the problem also is the difference between exited frequencies (ie notes) and formant frequencies.(ie the fixed resonances of a body). Pitch changer really struggle with differentiating these outside the context of vocal pitch correction (which still often leave highly audible artifacts).
Whether preserving the body (formant) of an instrument is the right thing to do, I do not know because really I do not know if a modern viola/violin/cello/guitar etc body is different to that from a couple of centuries ago.