Ali,
You mention:
i have lost count of the amount of times i have had 8+ a/c line astern 10nm trail only to be told by dubai we need 15/20nm now.
That is because centre fire a stream of aircraft into Dubai airspace from a long range. The lead time required to sort the spacing out does not allow for tactical adjustments at a late stage. The solution has been requested by Dubai on many occasions only to be shot down in flames by RJ. They last asked when the airshow was on.
All they wanted was a hold to the North and a hold to the South under their control. Centre could supply the stream as requested but if Dubai runway requirements or unforseen events caused a change in the spacing at a late stage they could use the hold to finesse things.
Irrespective of how good or bad the controllers or the pilots are, proper airspace design can only reduce the workload of all the players and lead to more efficient airspace and runway utilisation.