This could get interesting.
If George IV still dies as OTL, Charlotte I (or maybe "Augusta I") ascends the throne about when the Belgian revolt breaks out. This could trigger a number of butterflies. Prussia may be emboldened to intervene on King Willem's side (iirc the two kings are brothers in law) in the belief that the Prussian Prince-Consort will swing his wife against any British intervention, and that France won't intervene alone. OTOH, the Belgians may attempt to head off this threat by choosing a Hohenzollern (a Catholic Sigmaringen perhaps) as their king.
Then there's Denmark. Is it conceivable that Louise of Hesse-Kassel may be persuaded to marry a Hohenzollern instead of the future Christian IX? That scotches the Schleswig-Holstein business, since the King of Prussia won't rob a member of his own house, nor let anyone else do so.
Does the Crimean War still happen? If Britain and Prussia are closer, might we see a joint Anglo-Franco-Prussian ultimatum, forciing the Tsar to back down from war with Turkey?
Other thoughts?
She'll accede as Charlotte, I think. Charlotte was her first name and intended name as Queen. There was actually a row over Victoria; you see, her name was actually
Alexandrina Victoria. When it was apperant that she would be Queen of England, it was declared impossible she have such a foreign name. They suggested Charlotte, but in the end Alexandrina was dropped and Victoria was kept. So she was.
There are a lot of butterflies from her marriage; small, but sturdy. Belgium is difficult as it's still in it's infant stage: Willem I hasn't used his Hollandic Arthimatic to push through his constitution. Indeed, Belgium may remain part of the southern Netherlands with a disinterested Britain, especially if Prussia and Austria become active, or Britain has a Tory Administration eager to maintain a barrier against France.
I can't say much about Denmark except that you can't rule out the
Hereditary Princess Caroline she was senior to the mother of Louise of Hesse-Kassel and certain events lead a certain brother of George V to start wooing her... Louise could also end up a boy. Christian VIII may have more issue; a different Frederick may be born. Lots of interesting ways to go.
As for Crimea, only time will tell. Yes, Charlotte is married to a Hohenzollern Prince. But one must remember he isn't the King's son. He's his nephew, their nearest kingly relative to Frederick William II. Prince Friedrich is a romantic and may lean towards certain views, but I don't see him being a reactionary. as Prince Consort he may also do as Victoria did with Leopold: pushing him away as an adviser and taking control. Early on Charlotte and Friedrich too will have many influences, but it doesn't cement anything. She's Whiggish. He's Romantic and maybe a Tory. The Congress system will collapse, or rather in this TL, slowly decay, something will cause it to implode.
All I can say is expect a different succession in France in 1824; no rising in July, and a focus on
bright young things. Monarchs who reign within the mid 1820s and early 1830s; mostly in western Europe...
Just remember, Charlotte marrying Prince Friedrich does not equal a Anglo-Prussian alliance. He's not a son of the King, he's just a minor nephew. The only pluses over Coburg are that he isn't penniless (Leopold had an allowance was £300 a year. Not really suitable material to woo an heiress), he's got royal blood, and he's got connections to the house through the House of Strelitz, rather than some unnamed fortune hunter from Saalfeld who refused to come to England when Charlotte begged. He was cautious. It worked, but Friedrich will be different.
Prussia and England will be close, but they weren't on bad terms anyways. Friedrich may encourage an interest. He was a romantic like his cousin Frederick William IV, so I can see him being not too liberal... but I can see him being a
very moderate Whig. He'll definitely be somewhat supportive of the Tories though, which could influence Charlotte too if we see him schooling her.