Actually using the law and or Parliament to sort out the line of succession isn't that unusual
William I appointed his second son William Rufus as the heir to the English throne (didn't go down well with his oldest son Robert who "only" got Normandy)
Then the whole Matilda Stephen Henry II debacle.
A cartel of Lords invited the Dauphin over to usurp John and then had to backtrack very quickly to kick him out on John's death in order to have Henry III instead.
Isabella and Mortimer then depose Edward II to rule through a regency for Edward III - who then gets rid of Mortimer and shuts his mother up at Windsor before sending her to Norfolk for the rest of her life.
(Just for the fun of an additional complication)Edward III decides he has a better legal claim to the throne of France (via his mother) than the heir favoured by the French despite the fact French law is quite clear that no one inherits through a female line.)
RIchard II agrees to legitimise the Beaufort children of John of Gaunt's 3rd marriage provided they have no claim to the throne.
Henry IV deposes Richard II which ends up with the Wars of the Roses as Lancaster and York each think they have the better claim.
Edward IV deposes Henry VI
Edward supported by Richard then uses the law to debar the children of the middle brother George from claiming the throne as George is a traitor. (Otherwise when the children of Edward IV are declared illegitimate the heirs would have been Edward Earl of Warwick (whom Henry VII executed) and Margaret Plantagenet (whom Henry VIII executed for treason as an elderly women)
Richard III uses the law to declare his nephews and nieces illegimate to take the throne.
Henry VII claims to be both the Lancastrian heir via his mother despite the Beauforts not being legally allowed to inherit and by right of conquest.
Henry VII legitimises the York children again
Henry VIII wills the crown to his 3 children in birth order despite the girls being illegitimate and then skips over the children of his elder sister to go straight to the children of his younger sister Mary.
Edward VI tries to cut out his sisters. The throne should then have gone to Frances Brandon but she declines it in favour of her daughter Jane Grey. Mary I raises an army and takes the throne.
ELizabeth fights a constant rearguard action against those (Catholics) who argue she is illegitimate and want to put Mary Queen of Scots on the throne. She also keeps the other 2 Grey sisters at court, declares Catherine Grey's marriage to be invalid so her sons were illegitimate. On her death she appoints James I as King despite the fact that per her fathers will (which is what she based her claim to the throne on) the next heirs were the Stanley family (although they may have shot themselves in the foot as Ferdinando was remarkably reticent about what his religious affiliations were).
Then we have the Parliamentary deposition of Charles I, the restoration of CHarles II, the deposition of James II, the skipping over of the Catholic James III in favour of Mary and the crowning of her husband despite the fact he had no claim to the throne (except possibly via conquest) and then the search for a Protestant heir to Anne which led to George I (via his mother and grandmother)
Even when we get to Queen VIctoria - she was able to take the throne of Enland but the Electorate of Hanover went to her uncle as a woman couldn't have that one.
Thank goodness we have now got rid of the boys first messing around (although I'd love to see Princess Anne outranking her revolting middle brother......)