Besides this historical motivation, there exists no technical argument in favor of any of them.
I do not agree at all that Nihon-shiki can sabotage the ability of Japanese people to learn and pronounce English.
Except for the native English speakers, all the other people of the World who are familiar with other languages besides their own are also familiar with the fact that every language has its own system of writing and pronunciation, whose rules you must learn, including the alphabet variations.
It is the dominance of English in the international relations after WWII which sabotages the ability of most native English speakers to learn other languages, especially to learn how they are pronounced, so in foreign countries the native English speakers usually stand out much more than the native speakers of any other languages, because of their pronunciation, which is found funny by the locals.
Making the rules for writing your own language more complex for your own country and for most other countries of the World, just to make them simpler for the citizens of a certain privileged country, is not a behavior that I can approve, because I find it too subservient.