No one clogs up anything.
Most companies around the world have the policy of being stable by 1000ft IMC (500ft VMC) and probably your as well (should be in your AOM).
One has to remember that a 747 has a bit more inertia than a 737, and that combined with an average human brain time reaction to the unexpected may lead a few to show some respect to the third (vertical), and fourth (speed) dimensions for which we (pilots) have not being created to evolve in.
I find myself regularly behind 747’s on approach (including SIA) and never experienced any problem, but having some wide body experience (and over 30 years on the job) helps me anticipate accordingly (as I know what they will do within the next few minutes).
And yes, 230 IAS at 1500ft is definitely excessive even in a 737 (that I currently fly)
This is a culture issue; the only one you impress is yourself.