I first wonder if the difference is more in pronunciation idiosyncracies and pronunciation limitations of the two language groups than in the transliteration per se. I have thought about this idea of standardized transliteration but I think that would only exacerbate the problem because then each language group would pronounce the transliteration according to their own sound system. Here's an example. Many North Africans have names that are spelled in Arabic with a 'waw'. So the name Salwa (transliterated in English) would be pronounced by the French as Salva (English V sound). In that case, the French transliterate a name like that as Saloua, hence the ability to immediately distinguish someone having a name with 'oua' as North African and hence from a country colonized by the French. If there were a standard and that standard followed English pronunciation, the name Salwa would be often pronounced in France as Salva, losing the meaning in Arabic and eventually the connection to the Arabic language. Of course, standard transliteration would make some people's lives easier but I don't think it would solve the problem you're talking about. Something like the addition of new symbols to denote loaned sounds might be more helpful, as the Arabic alphabet has done with the p sound. It doesn't exist in Arabic but it's so common in loan words and proper nouns that Arabic writers have started incorporating a new letter to denote it. If you're talking about standardizing based on IPA or some linguistic system, it would also be hard because then you would always have to be checking names at the moment of transliteration to see what the linguistic notation would commonly be in the target language. So first transliterating to IPA and then to the target language. And we know that bureaucrats and individuals are not going to do that. :)

To go back to definitions, Romanization relates to writing a word, in our case Arabic, using the Latin alphabet. In itself, the process is laden with hurdles that relate, among other things, to the linguistic system to implement as a basis for Romanization. Following UN recommendations to adopt a unified, scientifically-based, Romanization system (Resolution No 9, UNGEGN, 1967), Arab countries are still facing implementation issues despite agreement on the now called Beirut System.

Reaching a consensus concerning Romanization would in itself represent a sizeable achievement. However, Romanization is confined to producing script. It has no control over how Romanized words are pronounced. Extending Romanization to actual pronunciation, if at all desirable, would imply the inclusion of diacritics that would have a negative impact on readability, and would depend on how important pronunciation accuracy is. Adding diacritics may sound reasonable for cartography, but not necessarily so for road signage.

I think the best way is to have a standard Romanization for Arabic which is truthful to the phonology of Arabic. Then it is up to the reader to respect that. Just like Italian, some say the Italian word just like Italians do and some don't. But what is important is that there is a correspondence between the Italian phonology and their writing system and others have the possibility to learn that if they wish.

there is an international transliteration system which is uded by scholars

Good Answer Jalal Maleki