I kind of agree with what you say here, but using water offering to describe the skillfulness of Dharma teaching, it seems like something missing, because the shape of the bowl is fixed, how you pour the water is limited, but human is so, so much more different, everyone and everybody are just so different that even Buddha has to create 84,000 method of Teachings.
Like the story of Kisagotami, she has a son that died suddenly, she didn’t know what to do, so she went on to call for help, trying to revive her son, and she just couldn’t let go, so Buddha used a very skillful way to make her realize, the story below:
She went to Prince Jeta's Grove, Anathapindika's Monastery, where the Buddha was staying. She arrived in the middle of a discourse being given by the Buddha to a large congregation. Totally despairing and in tears, with the corpse of the child in her arms, she begged the Buddha, "Master, give me medicine for my son." The Awakened One interrupted his teaching and replied kindly that he knew of a medicine. Hopefully she inquired what that could be.
"Mustard seeds," the Enlightened One replied, astounding everyone present.
Joyfully, Kisagotami inquired where she should go to obtain them and what kind to get. The Buddha replied that she need only bring a very small quantity from any house where no one had died. She trusted the Blessed One's words and went to the town. At the first house, she asked whether any mustard seeds were available. "Certainly," was the reply. "Could I have a few seeds?" she inquired. "Of course," she was told, and some seeds were brought to her. But then she asked the second question, which she had not deemed quite as important: whether anyone had died in this house. "But of course," the people told her. And so it went everywhere. In one house someone; had died recently, in another house some time ago. She could not find any house where no one had died. The dead ones are more numerous than the living ones, she was told.
Towards evening she finally realized that not only she was stricken by the death of a loved one, but this was the common human fate. What no words had been able to convey to her, her own experience going from door to door made clear to her. She understood the law of existence, the being fettered to the always re-occurring deaths. In this way, the Buddha was able to heal her obsession and bring her to an acceptance of reality. Kisagotami no longer refused to believe that her child was dead, but understood that death is the destiny of all beings.