They portrayed most of historical gangster characters wrong, not only Luciano. Rothstein was a sociable guy and not really a gangster, just a gambler and businessman with certain 'friends' and connections. In BE he is some sort of coldhearted "mob boss". Nucky was a corrupt politician, not a gangster and murderer. They made Torrio look like some stereotypical Italian mob boss while he was in fact a complex person and his and Capone's organization wasn't even a mafia, they accepted people of all nationalities and many non-Italians held important positions. In BE Nucky tells Jimmy that he will always be a stranger there because he's not Italian, but this simply isn't historically correct. Besides, O'Banion's gang wasn't all-Irish either, he had important Italian members while in the BE he appears as some sort of anti-Italian stereotypical Irish mobster. IMO there are too many ethnic stereotypes and hollywood cliches in the show when portraying gangsters. Lansky gives the impression of some calculating Jewish businessman but at that time he was mostly known for being a thug (he was still a teenager FFS, not some criminal mastermind à la Hyman Roth). IMO they got Al Capone right but him getting into petty fights at that point in his criminal career also seems a bit strange.

Anyway, BE is pure fiction and has hardly any connections with historical reality of that time, at least as far as the world of organized crime is concerned, other than using the names of real criminals. Atlantic City at that time was peaceful, there were no major conflicts, yet alone gang wars. The massacre we saw in the final episode was way over the top. 40 or something people dead in one night in an event we don't know anything about. St. Valentine's Day massacre killed 7 and it shocked the entire nation. Also, Negroes playing important role in prohibition OC, fighting with the mafia... Makes it look like some cheap blaxploitation movie to be honest. Some plots seemed totally unrealistic to me, for example Nucky plotting the death of a mafia boss as if killing Masseria would solve any of his problems (the rest of the family would simply move on as if nothing has happened? we're supposed to believe that or what?), not to mention he had no crew of his own.

Don't get me wrong, I love the show and watch it, but it could have been done soooo much better. I don't understand why they placed the series in AC and decided to have Nucky as the main character. He simply isn't interesting enough. If they wanted to make a good series about gangster violence during prohibition, the story should be focused on Chicago or New York and main characters should be guys like Capone, O'Banion, Bugs Moran, Lucky, Frankie Yale or some Jewish mobsters. Or perhaps Masseria and Maranzano, personally I would love to see series about The Castellammarese War.