I like the idea of having the Heir take over after a Sovereigns death.  I think that would make the Dynasty system better.  I too would like to see that in the game.

I would vehemently support the way Dominions 3 deals with this. If your pretender dies he can be "reformed" through a magical ritual which requires some time. (like 30 to 60 turns). 

The Channelers are supposedly immortal anyway so this wouldn't be a big change. Plus there might be some sort of spell that leads to Sovereign perma-death if used? 

The problem is that killing them in friendly territory doesn't end the game. It only ends the game if they die in hostile territory. Which means that while I can run around adventuring and such with my sovereign, I really don't want to use them in an invasion force.

It's lame.

What the game needs is a mechanic that keeps a "Remnant" of a defeated faction once the Sovereign is killed. Of course this will only happen for defeated factions in a single player game. The mechanic of Sov Death = Game Over isn't going to be changed. Something though should be done with the parts of the enemy faction that would be left over if the faction still had towns left.

Any champions still alive that could cast magic because they were "Imbued" by a AI Sovereign should loose the ability to cast magic. Any towns that are left on the map should remain on the map but turn into "Minor" factions. Their names could be changed based on the faction they belonged to originally or based on any of the Sovereign's offspring that are still alive on the map. If you defeat the Sov of Kraxis and Kraxis still has two or three cities left, the surviving Minor faction would be called the "Remnant of Kraxis". Most of the Sovereign's armies should disband if they haven't been defeated with the exception of those in a city and if that city can afford to pay the unit upkeep on those units based on it's gold production.

That sounds like the most "Logical" solution to me, but, I can see where this could take a while to put in. Hopefully though in time we'll see something like this because seeing cities and towns just vanish into thin air is pretty weak IMO and reeks of non-creativity. There's also a really good opportunity here to further incorporate the Dynasty System and make more use of it for enemy factions. Surviving Faction Heirs of AI factions could keep their essence and continue on as a new faction once their Sovereign is destroyed, which could greatly increase the length (and fun) of a game.

My suggestion from similar thread:

Have a resurrection shrine in the capital that will resurrect the sovereign some number of turns after his death.  In order to take out a sovereign, you'd need to kill not only him but also destroy the resurrection shrine in his town before he resurrects.  During the period when he is dead, his kingdom would suffer some sort of suitable penalty such as low troop morale.  Also, if the resurrection shrine is destroyed while the sovereign is alive, allow it to be cheaply rebuilt in any town so that a player isn't screwed if he happens to lose his resurrection shrine early.  Or not.  Maybe a player should be punished for not better protecting his resurrection shrine.

Also, make sovereigns resilient and difficult -- and dangerous! -- to kill.  Offing a sovereign should be a really big deal.

I'm cool with Sov death but ONLY...I mean ONLY, if the dynasty system is as robust, entertaining, and worthwhile as Crusader Kings. Currently, it is not even close.

The dynastic system in that game was a fun little metagame in it's own right, but what we have is a shadow of that. If that was not significantly expanded, I'd only see Sov death as the downside without any of the upside of monitoring huge extended royal families with internal politics, and a wide variety of traits that affect their offspring.  Sov death in itself does not make this system. 

Make that system first, then we can talk. And clearly, we're probably not likely to see expansion in that area any time for the next year, as there are much larger priorities.