The clef and transposition override feature is great. I have used it surprisingly more often than I originally thought I would. There is one, admittedly rarer, sub-feature that could be added however, and it involves scores in C.
In some tonal 20th century writing – Prokofiev being a prime example – a full orchestral score could be presented in C and include key signatures for all instruments including trumpets and horns. However, individual parts for these brass instruments would be published without key signatures. This makes the score more consistently “In C” and easy to read, while keeping the historical practice of adding accidentals in transposable brass parts in lieu of key signatures. Since Dorico understands the presence or absence of key signatures as two separate instruments, this currently cannot be achieved without duplicating instruments; but it could perhaps, if ever implemented, live in that “clef and transposition override” dialog box. This is of course only required for historical reproduction since contemporary practice allows key signatures in both trumpet and horn parts; but I still thought that it wouldn’t be a bad idea to ask.