A pitch setting for midi instruments.

Midi instruments should have a slider in their properties that allows you to control the speed/pitch that notes will be played at, so lower will play a note slower and deeper, higher would be faster and higher. It would allow for a lot more control over the sound of your midi's.

Here is an video example of what it would look like:
https://www.youtube.com/watch?v=nvGW0jloIhQ