So, do you agree the merge is justified?
I'd say "no", though it is clear that the tags need a little work (and I'll be too busy to do it for several days).
I would not like to see optics removed as it is a name with considerable history and a precise meaning to people working in the fields.
On the other hand, we do serve beginners here, and they will mostly likely fell that their questions are about light.
None, that I can think of, with one caveat: the most fundamental description of light comes from QED, which is way beyond my background. A question about the QED description of a photon could be called an optics question only in the most pedantic sense. However, in practice somebody asking a question about photons in QED would be better off with a tag like photon or qed. The term "light" generally refers to macroscopic phenomenon, so I don't think the overlap with QED is really an issue.
As further justification I'd argue that by definition, any question about light in situations where QED is not required, even if some degree of quantum mechanics is required (eg. lasers or spectroscopy), falls under the domain of optics. As I said in the tag wiki for optics, "Optics is the study of light, and its interaction with matter."