Colour changing LED dependent on temperature.
I think it would be a great feature to be able to change the colour of and LED based on temperatures of your printer. You could do it based heated bed temperature or the print head temperature or even the build chamber temperature. That way at a glance you can easily see if the printer is operating correctly.
For a given temperature parameter, such as printer head temp, you could select the given range above and below the desired temperature and then select the colors which should appear over that range. Eg blue at the bottom moving to green when the temp is perfect and red if it is too hot.
I hope you decide to implement this as a feature.