I think something like this would be very desirable, but I would implement it differently. I would allow to edit soloed or muted tracks when you hold the corresponding button (solo or mute). This is the most immediate solution with no delays. In other words, pressing down solo or mute button would engage the edit mode. Releasing solo or mute button would exit the edit mode and toggle the solo/mute state of the entire machine. The drum pads would remain playable as long as you don't hold those buttons. This is actually how I expected it to work initially.