Unlike other games Elemental isn't a game about an empire (in Civilization you aren't playing Stalin or Washington, you are playing Russia or America), its about your sovereign.
Hmmm, that may have been the original intend but with so many heroes to care for, cities to build, trade, diplomacy, exploration, neighboors to manage... It is just that, a fantasy empire building game (Civ Fantasy if you will). There is nothing other that binds you more to your sovereign then it does towards your other heroes, in fact given that you loose your empire if your sovereign dies he's best suited to spend his life locked away in the capital with an escort to quickly move him off in case of a threat.
I'm undecided on the question of succession. On the one hand it gives a very cool use to the dynasty system. On the other it changes the focus of the game from the sovereign to the empire. We are talking "psychology of gaming" stuff here (attachment and agency) but I tend to think that although I like the idea of succession, it robs Elemental of one of the things that makes it unique. Unlike other games Elemental isn't a game about an empire (in Civilization you aren't playing Stalin or Washington, you are playing Russia or America), its about your sovereign. I wouldn't mind a option (or faction) that didn't need cities at all, that just raided, camped and caused chaos. Succession dilutes that focus on the sovereign.
But succession is also a very cool concept, especially in considering your sovereigns bloodline (if it was in, I like the concept of being able to have your amazingly talented kid kill off his parent and assume the throne if you decide you like the kids talents better). But at the moment I'm against including succession.
Imho, if you make it so that the appointed successor inherits the sovereigns abilities and stats if below them or gets an additional bonus if he's above them along with all the goodies and stuff it could work, maybe even consider a single death to a sovereign to be acceptable but turmoil (ie loose the game) to hit when the successor dies off as well before he's being succeeded by one of his offspring (minimum rule of 100 seasons or so). This will enhance the whole attachment and agency stuff imho, it sure makes more sense then to have this immortal sovereign in each kingdom or empire. Add in naming your kingdom/empire and you can have them automaticlly be named %name% the II of %country% etc... Also opens up the posibility of assisination units/spies etc.