She really was the most unpleasant of any of the heads of state during Korra's time. Hou-Ting was an egomaniac with no remorse. I honestly would have loved to see Zaheer raise the temperature of the air inside her body to give her heatstroke and render her permanently braindamaged. I know that Raiko was an idiot with no redeeming attributes, but Hou-Ting was actively selfish, malevolent, and a literal slave-driving hag who was detestible along the same lines as Dolores Umbridge from Harry Potter. The same kind abuse of legal authority over others and doing so with a smug smile and unbridled arrogance.
Both of them are two of the people in fiction I hate most of all. Having her being burned to death or having her skin frozen off and paraded skinless would have been similarly satisfying to having her suffocate to death to Zaheer's narration in Henry Rollins' iconic voice.