I have to agree with Nerhesi.
There is a difference between removing things from a game that add very few fun and complicate things too much and removing things that really make a difference.
Removing your sovereign from the board removes a very special feature and the benefit is far less than what is lost. The solution achieved in LH was pretty decent and I don't see why SK cannot have the same rules regarding your sovereign (and no, "differentiating SK from LH" is not a valid reason )
We know that the sovereign has to be some sort of "immortal" not diying even if the full army loses a battle, but there are ways to penalize the player for losing a battle with the sovereign in it. The sovereign can lose experience, the kingdom can have bad morale for several turns, the magic pool can diminish and even a percentage of the population can flee the cities in despair.
In fact, to make the game real epic the sovereign unit should be present in the force that fights the final battle against the Sovereign King. Do we really want our sovereign to be a coward, or a hero?