> One might object to the dominance of English as a lingua franca, but actually any other languages being the lingua franca would dominate the Romanization system as well
Kunreisiki is not a system dominated by any particular lingua franca; it's a system that directly reflects Japanese ways of writing Japanese. One could imagine e.g. a Spanish-influenced romanization system that would represent the は-line in a way that corresponded to Spanish orthography becoming popular in a world that was dominated by Spanish as a lingua franca, and that would have the same problems that Hepburn does. But Kunreisiki really is "neutral" in that sense.
In short, it seems to make the Latin alphabet work for Japanese. Perfectly fine if Japan uses it as its Latin-based writing system (discarding the native ones), or to transcribe it for academic usage, but unhelpful as a Romanization, which is mostly intended to make it easier for people completely unfamiliar with the language to pronounce names and to learn the language.
Kunreisiki is not a system dominated by any particular lingua franca; it's a system that directly reflects Japanese ways of writing Japanese. One could imagine e.g. a Spanish-influenced romanization system that would represent the は-line in a way that corresponded to Spanish orthography becoming popular in a world that was dominated by Spanish as a lingua franca, and that would have the same problems that Hepburn does. But Kunreisiki really is "neutral" in that sense.