I think you're missing a farily fundamental point...
You still have 1000'/500' remaining to sort out this 20K problem... Your "gates" as you get sub 100' should not be as wide as this.
Since most types will use a "theshold" or "final approach" speed of, say Vref+5, you are looking at 15K to lose over 1000'/500' - hardly a problem, and in "stabilised approach" criteria will not need "idle" thrust to lose, just a little less than normal approach power.
The approach can therefore be considered stabilised...
All your concerns about wet runways etc are a completely different issue.
At BA we have the 20K at 500' limit, and completely different limits at the threshold...