I wonder how EU4 is going to show dynasties and their heirs ruling different monarchies? I would like to see rulers, heirs (possibly multiple heirs) and their age regarding other nations. In your own nation, you should also be able to see the health of your ruler and his/her heirs. Let´s take an example, Sweden in January 1, 1560:
The Kingdom of Sweden:
King: Gustav I Vasa, age 63, health poor, stats
Order of Succession:
1st Heir: Eric, age 26, health good, stats (His mother was Catherine, the daughter of Duke of Saxe-Lauenburg)
2nd Heir: John, age 22, health good, stats (Mother was Swedish noblewoman Margaret Leijonhuvud.)
3rd Heir: Magnus, age 17, health fair, stats (Mother was Swedish noblewoman Margaret Leijonhuvud.)
4th Heir: Carl age 10, health good, stats (Mother was Swedish noblewoman Margaret Leijonhuvud.)
5th Heir: Katarina, age 21, health good, stats, wife of Count of Friesland (Mother was Swedish noblewoman Margaret Leijonhuvud.)
6th Heir: Cecilia, age 19, health good, stats, unmarried (Mother was Swedish noblewoman Margaret Leijonhuvud.)
7th Heir: Anna Maria, age 14, health good, not matured yet (Mother was Swedish noblewoman Margaret Leijonhuvud.)
8th Heir: Sofia, age 12, health good, not matured yet (Mother was Swedish noblewoman Margaret Leijonhuvud.)
9th Heir: Elisabet, age 10, health good, not matured yet (Mother was Swedish noblewoman Margaret Leijonhuvud.)
In this way, I would like to see the family of ruler to be more natural. In this case, it would mean that once Erik would inherit Gustav then he would also have a weak claim to the Duchy of Saxe-Lauenburg through his mother. This means that he or his children could inherit that duchy or he could enforce his claim by force if he dares to fight against HRE military forces. All other Gustav´s children would not have any foreign claims.
That would also limit the number of royal marriages available. You should also be careful about them because the children produced by the marriages would be potential claimants to the throne.
The Kingdom of Sweden:
King: Gustav I Vasa, age 63, health poor, stats
Order of Succession:
1st Heir: Eric, age 26, health good, stats (His mother was Catherine, the daughter of Duke of Saxe-Lauenburg)
2nd Heir: John, age 22, health good, stats (Mother was Swedish noblewoman Margaret Leijonhuvud.)
3rd Heir: Magnus, age 17, health fair, stats (Mother was Swedish noblewoman Margaret Leijonhuvud.)
4th Heir: Carl age 10, health good, stats (Mother was Swedish noblewoman Margaret Leijonhuvud.)
5th Heir: Katarina, age 21, health good, stats, wife of Count of Friesland (Mother was Swedish noblewoman Margaret Leijonhuvud.)
6th Heir: Cecilia, age 19, health good, stats, unmarried (Mother was Swedish noblewoman Margaret Leijonhuvud.)
7th Heir: Anna Maria, age 14, health good, not matured yet (Mother was Swedish noblewoman Margaret Leijonhuvud.)
8th Heir: Sofia, age 12, health good, not matured yet (Mother was Swedish noblewoman Margaret Leijonhuvud.)
9th Heir: Elisabet, age 10, health good, not matured yet (Mother was Swedish noblewoman Margaret Leijonhuvud.)
In this way, I would like to see the family of ruler to be more natural. In this case, it would mean that once Erik would inherit Gustav then he would also have a weak claim to the Duchy of Saxe-Lauenburg through his mother. This means that he or his children could inherit that duchy or he could enforce his claim by force if he dares to fight against HRE military forces. All other Gustav´s children would not have any foreign claims.
That would also limit the number of royal marriages available. You should also be careful about them because the children produced by the marriages would be potential claimants to the throne.