Aegon rubbed his brow tiredly. So any plans to undermine Jon Snow from the North would likely fail. Thinking on it, it would also be too problematic for a mighty vassal to be dragonriders. They would be able to revolt and challenge the crown at any point with high chances of success. Not to mention the claim to the Seven Kingdoms that Shireen Baratheon's progeny would give their future generation. No, he would not leave such a dangerous problem to his future descendants.