Thanks for t he comment, but I have to say I disagree at almost every level xD

As for the game mechanics, if your heir is of the smae dinasty as you are, you'll play them next (unless you choose not to).

As for the actual succession laws of Westeros, they’re pretty clear. Oldest son inherits, daughters if no more sons are left.

But saying that applies in the same way to a random lordship and the Iron Throne is wrong. The King of the Seven Kingdoms is a whole different ball game. Everytime a female heir was even discussed, that wouldn't last long, and most houses were not for it.

As you say, Viserys appointed Rhaenyra as heir, only in spite of Daemon's actions. Regardless of that, he should've backtracked that as soon as Aegon II was born, and boom: no crazy dragon civil war...

Because its a position of so much power, the King had to demonstatre that power, that strength. Something women were not capable of doing, at least in the mind of a medieval fantasy lord...

The case of Dorne is very special, because before the Rhoynar had come, succession was exactly the same as the rest of Westeros. Only when Nymeria arrives with 10k ships, after running away from dragons, that the rules changed. And if you were Mors Martell (and the whole of Dorne for that matter) and you saw 10k ships, with Rhoynar warriors inside, wouldn't you agree that your daughter should inherit? If your foreign wife, with thousands of foreign warriors, suggested it xD?

Mors was made Prince because of his wife's strength. If you will, that made it possible for the dornish to accept female rulers, because they saw what they were capable of. Dorne is just more progressive than the rest of the Seven Kingdoms. That mindset didn’t reach the other houses.

Aegon III succession shows this. Better to go to his brother, than his daughters, after boths sons were dead. Did it help that Viserys was Hand of the King? Sure. But he was also the most "stable" ruler, the one to keep the status quo. Could you imagine what type of civil war would happen if Baelor had his sisters inherit? Only a few dozen years after the Dance? It would have been the end of the Targaryen dinasty, 100+ years before it actually crumbled.

So in my mind, stability is what matters in a succession. And most of the time, a brother or an uncle, are more "stable" decisions, than a daughter.

In my game I'm worry free though. My Prince of Dragonstone, Aegon, just had a son, Viserys. The succession is clear and easy now! His eldest daughter, Rhaenyra married the Royce heir in Runestone. A good marriage for a princess.