Auckland has no sequencing tool. There is CAM which tries to spread the Traffic out. It is commonplace to have 6-10 arrivals within 60nm as well as providing approach control for NZWP and NZAR.
Visual approaches can really relieve the pressure when there are a lot of arrivals. In saying that as soon as it starts getting busy most Aircraft will go around the back. Where possible Aircraft are kept on the STAR with speed control but because the STARS mostly have 2 90deg turns on to final it is not easy. Vectors and speed contol give certainty and accuracey for Gaps on final (minimum Radar Sep 3nm at touch down so bigger Gap required as aircraft establish on Final), at times bigger Gaps required due conditions.
Yes sometimes you will be sped up to get into a Gap and then slowed down to fit into the sequence. Yes you might have been able to get past the one in front but not the 3 in front of them.
The NZAR MBZ and Training Areas sure don't help either.
RWY05 is pretty hard to use with most departing Traffic having to be threaded across arriving Traffic.