OICUR 12
The issue of speed control may well be one that bugs you. I suggest operations into an airport with no other traffic will fit your bill. It's quite simple really, ATC are just trying to get one landing aircraft after another over the given landing runway threshold a certain distance apart. There are many variables that can detirmine how this is achieved and how the result pans out, it's not always perfect, but 95% of the time it's pretty much on the money. Whilst the world of aviation is very much 3 dimensional - some would now say 4 - the radar screen is really a 2 dimensional display, and it's just a matter of juggling all the different variables to try and achieve an efficient flow rate, one aircraft followed in turn by the next.
Re your second post, having watched many hundreds of thousands of aircraft departing towards PORPA/PRAWN, I think I could honestly say that very few would be needing/wanting a lot more than 220/230KIAS before those positions anyway, and re your "when the dep is RNAV", well there are quite a few departures that are not RNAV, so I guess the lowest link in the chain has to be satisfied. Another issue is separation on departures. With the terrain that we have here, if aircraft were departing with little or no ability for the Aerodrome controller to assume what your speed will be in comparison to the preceding, then we would end up with lot's of departures milling around PORPA/PRAWN basically together. Nothing much can happen until you are above the min Radar vector altitude (4100'). As airspace gets busier, then the procedures become more formated/rigid/less flexible.