What also must be borne in mind is the fact that there are both normal and maximum descent gradients predicated not only for precision approaches (eg - ILS @ 3 degrees) but also for NPAs.
In Australia these are as follows:
INITIAL Normal - 4%
SEGMENT Maximum - 8%
INTERMEDIATE Normal - Level
SEGMENT Maximum - 5%
FINAL Normal - 5.2%
SEGMENT Maximum - 6.5%
If you can contain any diving required within these criteria then you will remain within legal tolerances. If not then the approach MUST be aborted.
Case in point being the GPS NPA for RWY 23 at Dubbo, in New South Wales. At the FAF you may descend from 2500 feet to the minima of 1400 feet (1300 feet on Actual QNH). Problem is that at around a mile after the FAF there is a 1460 foot obstacle. In other words if you are so keen to drive it down and forget the maximum descent gradient then, even though you have passed a step which allows you to fly to the minima, you may very well kill yourself.
Constant descent is my preference but dive and drive does have a place WHEN USED CAREFULLY.