Leaving 'san' in is a perfectly fine translation philosophy only when the term and the cultural significance is explained in footnotes (or explained in the game.) If you'll note, more literal translations in literature are accompanied by hundreds of footnotes at the end, and more liberal translations in genre fiction usually aren't. This is because assuming the audience has prior knowledge of another culture while translating is an incredibly flawed translation philosophy. The idea that 'these words are incredibly common, the audience will know what they mean', which is an idea commonly floated, is weird logic that I don't subscribe to -> you translate for those who don't know the language, and thus during that process you don't assume that they already do, in fact, know the language. If footnotes are incorporated, or explanations, sure, feel free to keep honorifics in. But if not, then under no situation is keeping honorifics a satisfactory translation philosophy and I really don't give a toss what culture seekers think on the matter. Because you're translating for ALL non-Japanese speakers, not just a select portion of them.