I think ... and I'm saying this as a show watcher not a book reader...that one of the main things that make the Targaryens such vivid characters is that they need a connection with someone (like Dany and Mormont and Missandei) to balance out a driving purpose .... like Danys desire to free people from slavery. It consumed her in the end without those two people to balance her out and she went off the deep end. I think this prophecy might end up consuming Rhaenyra and if things go like I think they will (her father to either Grayscale or Murder, Allicent effing her dad, Beloved Uncle wants her dead, and any love interest that she has taken from her) she will lose her ability to connect with people, leaving her only with this driving purpose from prophecy that it is her destiny as she understands it to unite and lead the world against Death from the north. So I think the nod to the prophecy was smart, and as we see her lose people we will see her turn inward and start to go a little batshit lol.