Virote_Considon... I also believe that Hank O'Donnel should be given better Attack and Defense rather than "Bombard" ...there are enough units with that ability, yet the "special" one of a kind units should have an "edge". I will correct this.
Cloner4000... The Prom Queen could be set stronger (she only has a pistol and is Crazy) but basically the King Units you mention are set strong. In the hands of the AI, they will all die because the AI does not know how to use units "properly" as a Human does. They cannot even manage to hold on to Author for the Survovors. As a Human they will also die IF you fail to take into consideration the game factors and random play settings in the game engine...same for all CIV Games. Believe me, these factors and more have been taken into consideration.
There are game factors that cause stronger units to fall to lesser ones as I am sure you know.
As an example...When play testing, I set the Super Powerful M1 Mech alone in a Building that I just captured. The Zombies and Mutant Zombies Killed it and re-captured the Building because they had Major Hordes to keep attacking and finally Kill the M1 Mech in one turn. This is the Zombies Strongest Factor...Numbers! They now also have Very Strong Units later in the game so prepare yourself and play well. All part of the Challenge.
Keep in mind that we cannot control the Game Engine but have tried to work with it to gain the best end result for game play.
As a Human Player, use your Strategies and skills to preserve units you want to keep such as the Prom Queen and have the game play as you want. This requires that you understand as much as possible about this game. Play and read the Civilopedia as well as take into consideration the Random Factors and what you know about how the CIV Game Engine handles game play in general. You will discover your own approach that will help and please you most.
When setting this game over a period of months and playing many games for all factions...it was important to me to reach a game balance where even on level 12A, Normal aggression, a player could lose yet not likely. The Game should be Fun and challenging even on 12A level.
...be a Smart Human Player

Give yourself a chance to discover the additions/changes and the many possible strategies that you can play.
A fresh first time play will not show you all you need to know for any Faction.
I can tell you that when any unit is changed, it affects the game in ways that are not immediately evident. Far more complex than it seems. Get to know the Units you are playing with and when and how to use them...after playing and changing the game many times, there are units and settings that may not be understood or even liked but they were necessary for hundreds of reasons.
Hank O'Donnel, which is a "special Unit" that was not ultimately set with stronger settings than the SWAT for example, should, can and will be altered without a major game play change. Hank was considered as his settings were adjusted, just failed to keep his "special" unit status in mind as I was setting all others I was focusing on at the time. I don't expect anyone to really understand but the "logistics" involved for everything in the game is massive. I am sure King Arthur and I will be held responsible for game factors that we have no control over for example. The only way to really know what has been accomplished is to understand all factors.
Just so everyone understands, the former "Special Units" were kept in the game because they are there, expected and known...not because all are necessary really needed at all.
I also believe that any special one of a kind unit should be special... and not easily killed. It may strike you as "Funny" but if all units are special, then none are, if you get what I am saying.
The King Units that are of importance in the game are all set with Overkill Stats...but that does not mean that they will not be killed off easily IF you play them without careful thought and understanding. Even then the Random play factor can get them killed.
everyone plays a little differently and will want different unit settings to be in the game to suit their personal preferences but please get to know the game play and units first.
Sorry this was long but striving to convey more info here.