While the stuff about Diana in that article has been well documented elsewhere, Caroline of Brunswick was treated appallingly by her husband, George IV (and Prince Regent, of Blackadder fame, to his father Mad King George III) who would these days be readily considered an abusive husband.
It's been popular history for years that Queen Mary (of Teck) and her husband George V (our late Queen's grandfather - and btw where is his responsibility in this?) for sending their epileptic son John to live out of of public view and they've both been criticised as cruel parents.
However, it's also believed that Prince John may have been autistic too with behavioural issues that worsened as he neared his teens. Even by the standards of the day, where those with disabilities were kept hidden, the treatment of John was kind. There's increasing evidence, and most recent historical views agree, that John was not shunned by his family and although kept out of public view continued to join his family as much as was considered possible at the time before his untimely death.
His health difficulties were such, that his siblings felt his death was a release for him and contrary to the view that they didn't care, his parents mourned him.
I don't know so much about Joan of Kent but she wasn't the only Queen of England to support a rebellion against her husband and given the lives of the medieval peasantry I'm not sure it's fair to write her off as a bitch!