Most of that is still describing the "what". Only the "(mutations, if you like)" describes the "how". And one might still wish to know how the non-photosensitve cell chose to become photosensitive. And it's not just the odds of that, but the odds that the environment was also aptly developing to cause/allow the change. I understand that the change doesn't have to be beneficial -- it just has to be change that the environment proves out to be workable. Still, the complexity of the whole is MUCH greater than just whether one cell can change itself.

Just sayin' y'know.

Your description, while well-laid-out, and perhaps even accurate, describes changes, the odds against which are still astronomical. I'm not saying we didn't beat those odds, I'm just saying that being able to describe a few million years in two paragraphs doesn't really scratch the itch of those really wishing to know the "how". And I have a certain sympathy for the skeptic.