Dubai has 2 runways, operated as dependent parallels (as in, take offs from the right are subject to spacing between arrivals on the left, to protect the go-around path).
Assuming 5nm gaps on final at 160kts, there is nothing unusual about 15nm spacing through DESDI and BUBIN at 250 or 230kts. Yes, 15 miles through each gate equals 7.5 miles on final, but only if you can all do 250kts to the threshold. No? Thought not. So....15 miles is normal through the arrival gates. If you have a go-around in the mix or if flow has not been imposed soon enough, larger spacing will be requested until the situation stabilises because, as many of you will be aware, the alternative is being vectored an extra 30 miles.
Until the operators stop scheduling flights to arrive ALL at the times mentioned by Canoehead, there will always be holding at DESDI and BUBIN at those times. While there are probably more go-arounds at Dubai than at comparable airports (thanks mainly to the GCAA requirement for double the ICAO-standard runway separation) and these add to the delays in the hold, the biggest single issue is the glut of arrivals at certain times. Incidentally, the preponderance of similar callsigns does not help!