For decades, Viserys has tried to please the people under him and maintain peace, but never really solved the problems and confrontations, despite how bad these problems and confrontations became, and it is the reason why these problems and confrontations were festered and erupted when Viserys eventually died. "The Dragon Family", as the name suggests, is ultimately a family drama. The death and violence that followed also hints at how badly the head of the family, Viserys, did.
Veserys' failure as a king was first and foremost a father, which made his family fall apart and weakened his court. His shortcomings were exposed since Viserys decided to let Emma have a caesarean section. Emma will die regardless of the cruel operation. But Viserys did not give Emma the choice. However, when it comes to Dimon, he respects his wife's choice.
Veserys always suppressed his family problems, and he thought it was the best way to bear all the weight of the crown on his own shoulders--unaware of how Renilla and Allison's children were mortal enemies. Because he lacks decisive action.
In addition to Emma's death, many of the pains of "The Dragon Family" can be avoided. For example, before marrying Alison, he should have discussed it with Renella. Instead, Viserys unilaterally decides to meet Alison, and Renilla thinks they have all betrayed her. In the next decade, Viserys ignored Allison's children and turned a blind eye to Renella's extramarital affair.
For Aegon, Emond and Helena, Viserys' failure as a father is that he did not give them the care that the prince and princess needed. On the contrary, in many of the decisive events of The Dragon Family, Viserys buried the problem, hoping that no one would continue to discuss it, and hoping that the problem would slowly disappear. However, even if those people don’t talk about it, the hatred in their hearts will continue to grow. This is why, after Viserys passed away, the entire incident of Blood Dragon Dance almost ruined the prosperity of Targaryen family . It can be said that Viserys could have done better, but he chose not to do that.