A list of the E Major pieces whose loss I most regret:

Brahms 4th Symphony slow movement heads the list without doubt
Grieg’s Morning from Peer Gynt, its crepuscular sweetness undermined in its new key
Spring from The Seasons by Vivaldi, its vernal brightness cheapened
The slow movement of Rachmaninov’s 2nd piano concerto, the clarinets’ accompanying triplets which I played many years ago with the National Symphony Orchestra in Zimbabwe dislocated by the new key
The slow movement of Beethoven’s 3rd piano concerto, its profundity (so evident from its first two piano chords) lightened

There are other pieces where the special characteristics of E major (warmth, richness, chocolaty smoothness) were not so intrinsic to my enjoyment.
For example, Chopin’s famous slow piano Study in E major I can listen to in the new F major without feeling cheated.