“If the teaching of doctrine does not develop [how it is approached] it is dead.” Another meaningless sentence which cannot pass parsing. Who says it is dead? You. What do you mean by dead? You don’t say.
Here’s a piece of doctrine, “Thou shalt not bear false witness.” How should one approach this teaching save to say that according to divine Law ‘one should not tell lies’? Show us how you can develop that doctrine by a different approach in order to similarly conclude that one should not tell lies. 
Or could it be that far from reinforcing a teaching by approaching it differently the aim is to reverse that teaching under the guise of development?
Methinks this is what doctrinal development ultimately  means to the ‘progressive’ Catholic.