It’s correct that memory maketh man as you point out. It is unlikely that after being resurrected that Christ has forgotten the event of his death. Its significance stands forever in law. I agree that we cannot be stripped of memory as it is what makes us whom we are. Rather, I feel, probably much the same as you, that the scripture may refer to the need to remember. Thus we will not bring these things back to mind because there will be no need for its recollection.
Time is also a factor. We live in the present and for a comparatively short time. Even within that space, unless the memory is still required it fades and the “space” within the neuron system either becomes redundant because it is no longer needed or the connection decays and is replaced. But the lessons of memory are always being used because they are universal not only to our behaviours but our existence. Consider inhibitions for instance - or also affections. Loss evolves into longing and longing becomes accepted as part of life and can become an equation so to speak with other feelings we may develop later on. Memory is accommodated along with new experiences but its values are separate. It’s another form of memory and develops into our ‘character’ of whom we are as an individual.
The final part of the issue is choice. If we are content, and unoppressed, happy, fulfilled; we naturally do not dwell upon things that no longer concern us. In this system we live under constant reminder of oppression, loss and change. That will not be the case in the system to come, for the former, needless, hurtful, unnecessary problems and stresses will not exist. Why go back there?
Indeed and on top of that there is the fact that memory is like gravity. No one really understands how it all works. Of course there have been studies into it and there are numerous research papers that delve into the mechanisms of memory and the various "types" of memory such as
Sensory memory/Short-term/working memory/Long-term memory/Prospective memory.... among others.
So how the "former things will not be brought to mind" is probably something that we cannot really comprehend as it involves processes that we can only guess at right now.
How, for example, in Jesus case we are told
(Matthew 3:16) . . .
After being baptized, Jesus immediately came up from the water; and look! the heavens were opened up, and he saw God’s spirit descending like a dove and coming upon him.
What exactly it means by the heavens were opened up we can't imagine but it would seem that at the time of his baptism and his being anointed with holy spirit, Jesus’ memory of his prehuman existence was evidently restored to him.
So did Jesus have such memories already in his brain but were somehow "blocked" until they were released at that time or did Jehovah somehow transfer those memories into his brain at that time?
It does not tell us, of course, but if Jesus had such memory already implanted from birth waiting to be released at the right time, then it would seem that there can be selective blocking of certain memories without that having any negative impact. So could that be the case that in the New World Jehovah will consider that certain memories can "erased" from a persons mind without affecting that persons persona because they are needless in the sense of not contributing to a persons life in any positive way.
Have we not ever experienced a time when we have said to ourselves "I wish I could delete this memory from my mind. I don't want to remember that situation as it causes me too much pain" Perhaps the suffering of a loved while sick in hospital although being part of life only serves to make a person sad that they remember the suffering that they could not alleviate. Some of these types of memories seem to be burned into the fabric of a persons consciousness and whether we like it or not will surface from time to time and can be so real that it is as if it was happening all over again.
Would Jehovah kindly "block" such memories as it serves no real useful purpose to have them recalled and only causes the pain of that time to return. Perhaps there are things that are better forgotten or erased
In Jehovah's case he not only forgives but also forgets. ( Jeremiah 31:34)
So perhaps the former things refer to just the traumatic experiences that Jehovah decides do not need to be kept in memory or are blocked in the sense that they will never be brought to mind ever again. Only Jehovah can really understand how memory functions and how it can be controlled in a way that is beneficial for any particular person.