I invite you to explain how it is a development (such as along Newman’s 7 notes criteria) and not a reversal.
I don’t profess to be a Canon lawyer, nor a theologian, but I will give you one example.
Without repeating all of what I posited in a different thread:
A, as of the date of the marriage, and for some time previously, has suspected B to have engaged in a number of sexual liaisons.
A expresses to A"s father, and to B’s brother, that A has had concerns re: b’s history, to which B’s brother admits “she has been a wild one.” A states before the ceremony that should B engage in further liaisons, A would divorce her.
Years pass, and B files for divorce (not A). A subsequently remarries in what, for all appearances is an invalid marriage.
A’s father has died.
A applies for a decree of nullity; however, A’s only witness is B’s brother, who suddenly has vowed fealty to sister B and refuses to provide testimony.
A, with no witnesses, follows through with the case and the tribunal state there is insufficient evidence as their decision.
The marriage is ontologically null as there is a presumption against perpetuity. However, A cannot provide evidence sufficient to convince the tribunal. Therefore, A is presumed to be validly married to B, and the second marriage invalid.
Amoris Latitia did not provide an alternative in place of a trial before the tribunal. There is a presumption that if a tribunal does not issue a declaration of nullity, that what they do is say the marriage is valid. They don’t declare the marriage valid: if there is insufficient proof, everyone - the original couple and the Church - are back in the position that the marriage is presumed valid. Additionally, it my be possible one or the other of the couple could try the case anew, under a different theory of defective consent; that would not be possible if there was a decree of validity.
Should A consult with a pastor and the pastor tells A that A may receive Communion, no doctrine has been changed. The first wedding did not result in a marriage as there was defective consent the day of the wedding. The fact that a tribunal may not feel there is sufficient evidence does not change the ontological fact of the defective consent on the wedding day. The doctrine is not damaged or changed by a finding and decree of nullity due to an ontological fact of defective consent any more than it would be by a tribunal that does find sufficient evidence of defective consent. No marriage is no marriage; so the first wedding resulting in a divorce is a matter of civil law, not ecclesiastical law.
It may be that the Church is saying that inability to provide sufficient evidence cannot be overcome by a properly formed conscience as to the ontological reality, but I don’t find any such language anywhere so far in the discussions. All discussions appear to presume that there is no defective consent.
If the reality is different then it would appear that no doctrine has been contravened.
So it may be that no doctrine that is being developed; but rather praxis which is being expanded to a limited degree.
As an aside, I don’t have a dog in the fight; I am simply observing.