One problem I've run into is when playing a gig outside during daylight hours. Even though I try to use some type of overhead covering to provide some shade, the red LED's on my keyboard (happens to be a SOLTON MS60) fade out to where they can barely be seen. In addition reflections on the display screen can make it very difficult to see the display. I've also had this happen on stages with bright overhead lights that happen to be at a bad angle relative to my setup. The display issue can be helped considerably by a tilting screen as they use on the Technics KN5000 and other Technics units. The red LED issue may be a bit more difficult. It may take another color or a totally different indicator approach. I don't know how many other players out there have had problems on outdoor gigs, but I have several musician friends who play keyoards and they all complain about the same thing. Most of us have made cardboard shields or some such thing for the display screen, but it does not solve the problem of the washed out LEDs.
Paul C.