I often wonder what the BRF would be like had Charlotte not died. We will never know.
Victoria would never have been born; that is a given. I'm not sure we'd have had Mary Adelaide of Cambridge, mother of Queen Mary either.
You bring up an interesting point and have got me thinking.
It's not just the BRF that would be different, but roughly half the thrones of Europe, and even potentially the whole world.
If Charlotte hadn't died there would have been no reason for her uncles William, Edward, or Adolphus to get married and have children (her uncle Ernest Augustus was already married and likely would have still had children).
There aren't huge implications for William not having married as he didn't have any children in his marriage, but Adolphus' line continues to exist today, and not just through the descendants of Mary of Teck (although without her we wouldn't have the current BRF).
Even bigger though is what the world would be like without Victoria. No Edward VII or any of his descendants. Which means no modern BRF and no modern Norweigan Royals (who descend from Edward's daughter, Maud).
No Victoria, and then there's no Wilhelm II of Germany - and thus potentially no World War I. You have to wonder how the world would be shaped without that one. Furthermore, Wilhelm's sister married Constantine I of Greece, so the shape of the modern Greek Royal Family would be changed - three of her sons became King of Greece, and her grandson was the last king/current pretender. One of her daughters married into the Romanian Royal Family and was the mother of the last king/current pretender.
Another one of Victoria's daughters, Alice, was the mother of another Victoria, who married into the Battenberg-turned-Mountbatten family, meaning no Lord Mountbatten, no Prince Phillip, and no Louise Mounbatten, Queen Consort of Sweden. Alice was also the mother of Alix of Hesse who married Nicholas II of Russia and introduced hemophilia to the Romanovs. Gotta wonder how history would have been different had Nicholas married someone else.
Victoria's son, Alfred, had a daughter, Marie, who gave birth to a King of Romania (Carol II), a Queen of Greece (Helen), and a Queen of Yugoslavia (Maria). The modern Romanian and Yugoslavian Royal Families descend from her. Another of Alfred's daughters married Cyril Vladimirovich and is the grandmother of everyone's favourite claimant to the throne of Russia, Maria Vladimirovna.
Another son of Victoria, Arthur, fathered a daughter (Margaret) who married the King of Sweden, and the modern SRF descends from them. Also descending from them is Margrethe II of Denmark and Anne-Marie, Queen Consort to Constantine II of Greece.
Victoria's youngest child, Beatrice, was the mother of Victoria Eugenie, Queen Consort of Spain and wife of Alfonso XIII. Juan Carlos I is their grandson, so there goes the current Spanish Royal Family.
But there are other implications too. The Belgium Royal Family is not descended from Queen Victoria, but they are descended from Leopold I of Belgium. Leopold was Charlotte's husband, and likely would have never became King of Belgium had Charlotte lived - and certainly wouldn't have fathered any of his children, including the son from whom the Royal Family descends, as they were all born to his second wife.
The other interesting aspect is the Kingdom of Hanover itself. If Charlotte had survived then she would have been the first woman in a position to inherit the throne - as history went, no Hanoverian monarch had only a daughter to inherit his titles. The only woman to come close (at that point) was Victoria - but it wasn't really in her uncle's interest to change the law of succession so that his niece could inherit all his titles over his brother. Had Charlotte lived into her father's reign, however, it may have been more in George's interest to have that changed - he surely would have preferred his child, even a daughter, to inherit his throne in Hanover over his brother.
If the Hanoverian throne hadn't been separated from the British one then you have to wonder would German unification have happened under a Prussian dominance? And if it hadn't happened under the Prussians, who would it have happened, or would it have happened at all? How would 20th century history have turned out had it not happened?