This. Orchestral scores in C. The conductor needs to know how it sounds, the player needs to know how it’s played. (Band scores on the other hand, that transposed tradition will never go away…)
Note to all composers: write your scores in C. The usual octave transpositions are ok. I spent 6 weeks deciphering the chords in Elektra. After that I decided I’ll not put any conductor colleagues through that unnecessary ordeal with my own scores.