I would love to see something like a timeline editor where you could drop in midi events. And then label each section in the timeline based on sections you have created in the song for automating the scrolling/highlighting of that section. So if I have a song with the following info entered in to it.
V1:4
C1:4
V2:4
C2:4
B:2
C1:8
BPM: 100
Duration: 3:00
Arrangement: V1:4, C1:2, V2:5, C2:4, B:2, C1:2, C2:4
I could do something like, at this measure/beat/time marker, send midi preset "Guitar Lead", and scroll to or highlight section V1. Then drive the entire arrangement of how the song is displayed by how the sections are arranged in the timeline. And maybe using metadata (whatever the term is), have shortcuts for stating how long each section is. V1:4, C1:2, V2:5, C2:4, B:2, C1:2, C2:4. Then have Bandhelper spit out the initial timeline based on the arrangement info. The ability to quickly 'drag around' sections/midi events within the timeline for when at practice they say, oh, lets do C1 twice, and move the bridge over here instead...
In my case, I'm not looking to send a bunch of midi data. I just play with a band that uses an iPad app for click and some backing tracks (the app they use doesn't send MIDI currently). We get a count in and every song is pre-set to a specific BPM and arrangement. So I could have everything I need for arrangement/patch changes using the timeline. Then when the beginning of the song starts, I just trigger the automation track to start, which then should follow the BPM, and trigger presets/jumping to sections based on the timeline. Once it's figured out for the song, just hide it and enjoy the automation.
Hopefully all of that makes sense. This would be killer functionality (at least to me

)