I think 411A is being slightly disingenuous to the younger crowd...unless he has already pointed out that thanks to the marvelous feature incorporated in the 1011 known as DLC (Direct Lift Control), he can make the vertical navigation changes with little change in pitch attitude once landing flaps are set...he doesn't really "dive", he "sedately sinks" and then drives. It is the Cadillac, and always will be.
The fifty foot addition likely has more to do with the approach design criteria. In many cases, the authorities may not have the data to substantiate the missed approach obstacle clearance requirements if the missed approach climb begins at an altitude below the MDA. It is not that it can't be done; just that they have not done it. I note that my current employer adds fifty feet to any non-ILS approach flown with either constant rate or constant angle procedures, unless it has a published VNAV DA. I imagine that some authorities may have different interpretations.
When I look at the confusion generated by the introduction of constant angle, VNAV procedures, I often wonder if more error potential has been introduced than was removed. Nonetheless, the dive and drive technique has a poor history worldwide with respect to CFIT. I also imagine that a VNAV coupled constant angle approach will lead to far fewer misses over time, simply because the captain will be satisfied that the airplane is in a position to land more often than with earlier techniques.
In any event, as I often remarked to trainee pilots years ago, the term "non-precision" in non-precision approach refers to the accuracy of the signal in space...not to your flying technique...whichever one you choose, in this case.