It's a sign of the times, Emirates encourages the maximum level of automation at all times which is all very well in the perfect world however pilots ability to think outside the box is becoming limited. Not our fault just the culture that exists within the airline. For the ATC guys the airbus managed descent speed can be as low as 270kt(and often the aircraft flies slower) in the past we would change that speed to a minimum of 300kts but we had a notice saying don't do that you must use managed speeds at all times( and a high percentage of people take this as gospel).
ATC have a part to play in the erratic descents as well as poor descent managment from the pilots.