Maybe I'm missing something? In order to write a midi track for a transposing instrument, Bb clarinet, say, I have to open the inspector, find a little box that says "Key" ??? and then either mouse drag or cursor up/down to get a transposition? Would it be that big a deal to allow numeric input, and get rid of the label "key"? In a typical 60-staff orchestral work, you need to set clarinets, horns, saxes if used, double bass, plus others like Eb clarinet, english horn, etc etc. "Mousing" a number with a slider is a really awkward thing to do, and the clarinet needs exactly two semitones transposition, not "approximately 2".
And please, feature suggestion, put this back in the track "mix" fields, along with volume, pan, Vel+ (whatever that is).