I would really like to see a one-click method, where you could select a harmony, distribute them to say, Trumpet, Tenor, Baritone and Trombone (bass or treble clef choice)and have BIAB spit out the parts pre-transposed. Most of the logic is in there, but requires a lot of manual steps that could be orchestrated. Also nice would be a setting to choose to harmonize, for example only melody notes >= a quarter, half or whole. While I'm at it, it would be nice if the lower parts could optionally continue "drop notes" to match the harmony while the top part holds the melody.
Oh, and by the way, by the next release is a perfect timeframe ..