The bottom line is, air traffic is getting more and more. Therefore, Atc have to handle this big number in the air. But with modern technology and better radar system, it helps a lot for air management and sequencing. It's how much the Atc willing to put their creativity in making the flow better.
Making the plane to fly at 180-190 kts. or even slower at 30 nm from touchdown is too draggy. If that was the case in KUL TMA, I wish it should have been revised to 220/210 knots. Basically, 737-400 Vref on max landing weight is around 10 knots lower than B777. Where else 744 probably have 20 knots higher than 737's. Most boeing planes do fly Vref plus 80 for flaps up speed. And most of the time planes landing at well below max landing weight (unless on emergency). I can quote B777-200 Vref 30, is 138 knots (max landing wt) and plus 80, would mean 218knots is flap up speed.
And as for KUL TMA, I can't remember if there is/are many prohibited zone in it. Unlike other airport like JFK, Washington DC or even Seoul/Beijing. These airports have many prohibited area where it restrict the airspace utilisation. Modern day radar have a lot more info on the screen (unless KUL still using the 3rd. world facillities) ie. distance to touchdown, Ground speed, etc..
Recently I flew into SIN. Radar told me to cross a waypoint near NYLON (can't remember the name) at certain time. By doing so, I could adjust my speed well ahead from top of descend and avoid dragging the plane with flaps. It was a smooth sailing. KUL could do the same. Give the time to cross a fix which probably 10 nm on final (to be done by control sector) and let the pilot adjust the speed. Most modern day planes have FMC. So, setting up your descend speed correctly will give you the exact time over the fix.