Your wife sounds very nice.

She made some wise comments to you. I especially agree that you know more about your T than you think and that it would be a good idea to write it all down.
I'm sorry that your T wouldn't tell you more, though. I know I would be angry about that too. Maybe she wouldn't have been as effective as a T if she had been different. She sounds like a strong person. I can't imagine working on preparing for my T's death though I worry about it all the time. There are no guarantees in life for anyone, healthy or not.
What does "knowing your T" mean to you? What would you have liked to know? Can you write out a questionaire and then see if it's what you really wished to know?
I never told my mother that I loved her before she died either, and I regret it too. I sort of told my T that I love her, but not totally directly.