No routines have priorities over any other routine. I think Amazon is trying to keep a fine balance of ease of use and functionality. When it comes to routines, they could make it as advanced as a programming language. That would make it too complex for most people. But it is likely that Amazon will keep it simple due to the fact that most people will only understand and use the most basic routines, such as turning something on at a scheduled time or a trigger from a motion sensor.