Louis XI’s first son was born in 1458, but died in infancy. His next son, Joachim, born a year later, went the same route. And he remained without male issue until 1466 (called Louis in some sources, François in others), but this son also didn’t live long. Finally, in 1470, Queen Charlotte gave birth to a dauphin that later became Charles VIII. She gave birth to a second son, named the duc de Berri, in 1472, but, in emulation of his older brothers, died the following year.
Louis died before Charles VIII reached his majority, and thus appointed Anne de Beaujeu as regent for Charles. Anne steered the ship of state until after Charles’ marriage to Anne of Brittany, when she and her husband both fell out of favour with the new queen. As far as I understand it, majority in France was 13, which would’ve been June 1483 for Charles, yet his father (who only died in August) seemed to think that a regent was necessary (why?).
Now, if one of Louis’ elder sons (Louis (b.1458); Joachim (b.1459); Louis-François (b.1466)) had survived, would Anne have still been appointed regent? And how might things have gone differently for France if we had an alt-Louis XII, complete with wife (Marie of Burgundy seems the most likely candidate for Louis or Joachim; Elizabeth of York for Louis-François) and possibly children succeed instead of Anne’s lengthy regency? Obviously the chance of annexing Brittany by marriage (if it still arises) might have to wait a generation – Louis (b.1458) might have a son of Anne of Brittany’s age, though, but how else might things be different?