[This article is still a very rough draft. This article is a brain dump in response to a request for opinions on Noto CJK, so it addresses perceived shortcomings from a user point of view. Some of these shortcomings are not inherently the responsibility of Noto at all.
Noto CJK and Source Han have single-handedly created a Pan-CJK market and raised the bar for CJK support by its extensive character set and variants support for mobile devices, even surpassing default installs of desktop operating systems. This article envisions a perfect implementation, which may not be realistic given resource constraints. Some issues are also very possibly completely out of scope for Noto.]