I would to request an option for the core. My planned interface for my application only needs only one LED. The core main LED is bright enough for my needs. I would like a firmware option to put the Spark Core status on the secondary LED and have the big LED application programmable. This would be just a simple toggle in the API as to which is showing the Spark status.
So you can totally take control over the “big” LED now, so I guess the new feature you want is moving the breathing to D7 and the small blue LED? You know that don’t need the breathing LED (although I have come to find it reassuring)?
Here is how you take control of the “big” LED.
RGB.control(true);
RGB.color(50, 0, 0); // r, g, b 0..255
It would be cool to move the breathing effect to D7. It is definitely reassuring, but it’s also nice to use the RGB LED for something other than breathing.