This is just my take on this:
If it has an official English title even if it came on other systems (e.g. Trials of Mana, Castlevania Chronicles, Spy vs Spy: The Island Caper), it can be used. There is one SNES golf game where it does have an official English title in the ROM but doesn't appear in the game itself, everywhere else seems to use the romaji transliteration.
If it's a licensed game that only came out in Japan but... does have an official English translated title used in other forms of media e.g. Lupin the Third: The Castle of Cagliostro on the MSX, it can be used. This also helps regarding searching too because it would be easier to find.
but...
Anything else that doesn't fit into those categories, the romaji transcription is used.
Romaji has what I call a transcription problem because there are multiple ways a word can be translated and even different readings of the kanji. Similar thing to other ways of writing e.g. Chinese kanji, Korean hangul, any transliteration of Cyrillic based languages.
三 can mean san or mi. Even regarding names is tricky. e.g. Ōshima, Ōtsuka, dropping the accents Oshima, Otsuka or even adding a h Ohshima, Ohtsuka.
Then there's the issue of the names itself. Using the Lupin example (only because of familiarity and because the likes of both Lupin and JoJo's Bizarre Adventure have inconsistency regarding translation of characters/episodes/chapters to the point where the Lupin episodes ended up being Part X Episode X just because of the many names, worse in the manga when entire chapters got renamed even in its native Japanese again ended up using the Chapter X system), places like no-intro translate it as Lupin Sansei which is a half hearted transcription. As in Lupin is translated but not Sansei. If it was fully romaji, it would be Rupan Sansei or in the case of another manga/anime Bishōjo Senshi Sērā Mūn (Sailor Moon).
I've thinking of two ways regarding romaji outside of the licensed game problem (because of the translated name and the romaji)... One would be to use the no-intro (cartridges) or redump (discs) names that I think people do use... The other way would be to get the Japanese name and use
RomajiDesu to give us the romaji with the latter keeping the accents.