Dowries

I like the idea (because im "gung ho!" realism) but I think once again, you'd have to balance the importance of prestige over something like a shard. I mean a shard is going to give you mana, and allow you to cast spells of its element. To me, this is far more important than a hundred prestige points but that may just be me. However, if prestige gives lots of other bonuses it may be seen as a worthy trade-off.

I'd rather see a system where those things are all tied to that one princess. But in order for this to work we would also have to have noble families. All those possessions would be owned by the house and through their loyalty, you. Let me explain:

You, the sovereign, gets married, lets call you Merlin, Deity of Altar

Merlin is married to Theria but has no children as of yet

meanwhile, in your kingdom you have 3 cities. Camelot, Banbury, and Bromswell

Camelot is the capitol and thus where you and your family reside.

Banbury and Bromswell would be led by a noble family loyal to you, we'll call them uhh... House Yngalur  and House Brom respectively

The members of these houses would have children as well, and their daughters would be able to be married off as well. 

So for the sake of discussion let's say House Brom has a daughter, you would be able to pick whom she marries as her king.

Now heres where it gets interesting: 

If you marry her off to House Aachen in another nation, let's say the Empire of Kraxis, it would boost relations and trade with Kraxis and possibly your prestige in Bromswell if they are stronger, but then Kraxis would have a claim on that city (which would include its people, income, resources, shards, and maybe even armies if units have a "home" like back in the old Civilization days) if her lord father were to die without a son or heir. 

Thus it would be like a dowry, but instead of giving it right when the marriage occurs, it would come in the form of a claim. I think it might be easier done this way but again that may just be me.

I'd like to hear what you think  

Perhaps the dowery could be the property of the princess, but under the control of the faction into which the princess marries.  However, it would revert to the princess or remain with her heirs under appropriate circumstances.

For example, let's say for your faction has a charming, high ability daughter which you marry to your neighbor's faction to get the various benefits discussed above.  As dowery, you send Hero A, chest of gold B and you deed her city C which has certain strategic and economic values.  Hero A can now be given missions by the faction into which she married but between missions he hangs around the princess and guards her and her family.  His default loyalty is still to her.  If both the princess and the hero have high charisma, perhaps any army he commands may also become loyal to her.  City C is now a part of the faction into which she married but is her favorite city, perhaps she lives there.  If you and that faction continue to get along well things remain happy.

But, what if you and that faction quarrel.  We may find that your daughter remains most loyal to you.  Or, even more to the point, what if the other faction tries to assisinate her (or you) or declars war on you...does someting which tests her loyalties.  She and her hero A (and an army the other faction put him in charge of) and her city C may revert to you if the motivation is great enough.  If her chrisma is high, perhaps her husband and other parts of the other faction will now follow her.  Perhaps her children will as well, if her personality is strong enough.  After all, blood runs thicker than water.  Your entire wedding plans included the expectation that this charismatic, loyal daughter was a guarantee of your reltionship with the other faction....if they backstab you then you know (and they know, and you know they know, and ....etc) that this might happen.  Like a REAL diplomatic marraige, it seals the peace.

In other words, it may be interesting to go beyond the wedding being a simple ownership transaction, like selling a cow for breeding.  Instead it would be an ongoing, evolving transaction which adds to the implications of all future actions between the factions. 

I like the op version better, actually. It adds to the dynasty system in an intuitive way that is also simple to execute. Realism is nice, but get too many details and it starts to get in the way. Cleflar's idea sounds good, but you could probably stiffen the penalties for betrayal in simpler ways (prestige of the aggressor could drop by an amount related to the size of the dowry).

Your welcome to your opinion of course, but I just wanted to say my idea is really not that complicated at all.

@cleflar: This idea is nice but, in game, would you really give up all that stuff to another nation just to get rid of your charming, high ability daughter? I think not.

I do like your ideas on loyalty, I think we should always somewhat question our heroes motives, especially if they were brought to us in the way you described.

I guess I just got hung up on this:

It would be pretty easy to work out if the government type were to be feudal.

I think trying to work out "loyalty by character" would be very interesting, but tricky to implement, and very tricky to guess.  We couldn't expect the player to remember all of the various permutations, and would need to develop a system to show that City A is loyal to Character X, and City B hates Character Y, and so forth.  Cool concept, but it wouldn't scale well if we suddently have dozens of characters per Faction.

That said, I think having Cities have likes/dislikes for certain Factions could be interesting.  If City A is part of Princess P's dowry, and goes from Faction X to Faction Y, it might be nice to have City A be likely to side with Faction X in the event of war between the two.  You could present that information with a history screen, perhaps similar to GalCiv2's colony history page.  To keep things simpler, just give a flat "loyalty bonus" to the founding Faction, and provide a "Founding Faction's view" which would colorize all cities on the map to the Faction which founded them.