As previously noted, that is NOT a Boeing limitation on the 737.
We do it on a daily basis when we get slam dunked going into ATL (midfield abeam the airport at 7,000' then told "expect a short approach" and they turn you just outside the marker). Doesn't have anything to do with being unable to properly descent plan, some airports just expect you to operate like that.
Additionally, the amber SPEEDBRAKES EXTENDED light on the forward main panel doesn't come on unless the speedbrakes are extended AND the Flaps are in a landing setting (15-40). That light doesn't come on with flaps 1, 2, 5, or 10 with the speedbrakes out and there isn't a noticeable increase in vibration until you get to Flaps 10 with the speedbrakes out.
Just curious why Southwest doesn't allow it on their NG's, if it's a carry-over from the Classics and they don't want to intermix procedures for simplicity in training and line ops or if they have another reason for it.
Thanks, sorry for jumping the shark with the thread, we now return you to your instructional preparation for surrendering Captain's authority to the gate agents and flight attendants.