Ok JoeCo here goes. First of all you would never be handed off to Dubai Approach and told to hold, cos they aren't allowed to hold aircraft. You would probably be switched from UAE North to UAE West and told to hold cos UAE WEst is the holding sector that handles the traffic into Dubai from the West (as the name suggests).
As far as the slowing down and vectors and then switched to Dubai and given track shortening and high speed, I sympathise, as it drives us crazy in the Area Centre as well. We are told by Dubai what spacing they need through each gate (at the moment it is 20 NM in trail spacing during the busiest rush at night from 9pm till 3am local, and 15 NM at all other times unless Dubai asks for more), and so we have no choice but to use speed, vectors or holds to achieve that spacing. To vector the backside of someone and have them back to 250 KT's from top of descent only to hear them given high speed and direct UKRUM on first contact with Dubai App drives us crazy.
In saying that the problem for Dubai Approach is they are told not to individually coordinate reduced spacing so they are instructed that they are to leave on the 20 NM spacing even if they only need 10 between 2 aircraft. The flow system into Dubai is a dogs breakfast and both UAE ACC and Dubai TMA agree that it needs to be completely overhauled.
There have been ongoing efforts to resolve all this by bringing in a timed gate time based on the order of arrival on final, and then hopefully we as area controllers get you the pilot to meet the time at DESDI and as long as Dubai keep their hands off and allow you to fly the full STAR at 250 kts the sequence will work. Unfortunately there is still a fair way to go with getting that approved by all parties for a lot of reasons (a lot of them political).
I hope that gives you some insight.
Oh and on your point of slowing you down earlier enroute to help with the sequence, the problem we have is on one hand you are coming from Tehran Radar and we are lucky if we get correct ontime coordination of your flight from them let alone trying to pass on speed control instructions to them, and on the other hand you are coming from Bahrain where they have their own hell in a handbasket going on and have no time to try and pass on speed control instructions on our behalf. The result is we get you late where speed control is of very limited help cos with the strong Westerly winds we are trying to push you down to get you out of the wind, but if we issue you with speed control early you stay up high and we end up with no net gain, which means that we are having to resort to at least vectors, but most likely these days a minimum of 20 minutes holding during peak times.