Send all outputs to all inputs.
mute button on master channel!
Also: Amen Break Metronome and Renoise iPhone App
Already exists:Gainer + turn down volume = mute option at the on/off effect button.
Export song to Dialogic ADPCM
DIN sync (a usb adapter is shipped with every purchase of renoise)
Self-destruct button
3’44" sample generator
Automatic song genre analyzer
Print song
For me, the Auto Gain button on the master channel often acts like a mute button 
I’d really love to print songs
In what format? Just unzip the .xrns, open the song.xml file in an editor and print that. Bingo! Printed song 
I want the tracker layout and typography
Exactly! Besides, I want a proper print option in the file menu. A word processor would for example not ask the user to print the document in an external program 
Also, I think Renoise should have parental controls to block explicit content.
A command that overrides the fact that the maximum BPM is 999 and the CPU Overload Blocker and then sets the BPM so high it kills your CPU.
That would be useful. 
Pianorollol!
3D-support. Watching notes coming flying out of the screen while tracking must be a trip.
Cheat codes
Yeah! I’ll write IDKFA before my next tracking session!
Renoise will respond with:
“You try to cheat, No weapons for you!”
dongle
actually, if you could have a way to combine Renoise with Guitar Hero, that would be übercool.
Windows millennium easter eggs
Everytime you click a button, there should be an echoed very dramatic voice saying the name of that button. Imagine hitting play and it speaks “PLAY SONG play song play song…”, how awesome would that be?
Instantly close and shutdown the computer after two hours of activity. We all know you need to give your eyes a rest every couple of hours or so of computer use and this must be enforced! Don’t even try and save work before executing shutdown script (or maybe that’s a little too harsh.)