The show is killing off direct heirs, houses and names. Ep 2 drove it home. This could (and should) have huge repercussions for events in the books as a pattern.
Major houses are essentially wiped out unless there are more legitimate offspring or legitimization of bastards. I'm not an expert on the finer points of the laws of inheritance in Westeros, but it should be obvious the show is trying to drive this point home.
In the show, who would inherit the vacant lordships? No one we care or know about, unless they pull some surprises.
Baratheon: Robert's bastards and Shireen dead. Only the bastard Gendry lives in the show. No legitimate Baratheon heir (unless Stannis lives? but he'd have to have more kids anyway). So who in the show gets the lordships of Dragonstone and Storm's End?
Bolton: Roose and baby dead. There is only the legitimized bastard Ramsay as Bolton heir in the show.
Lannister: Tommen seems doomed and is a bastard anyway. Unless Cersei/Jaime/Tyrion have more kids, that's the end of Tywin's line.
Martell: Doran and Trystan dead. None of the bastard Sand Snakes are legitimized. End of Martell name in the show.
Arryn: Sweetrobin is alive for now.
Tyrell: Marg and Loras imprisoned. Willas and Garlan don't exist in the show.
Targaryen: Until Dany can bear children again, she's the only "legitimate" living heir.
Frey: Are fine. For now.
Greyjoy: Fine, though no children in the next generation. Kingsmoot anyway.
Tully: Edmure probably has a baby on the way.
Stark: By comparison to the other Great Houses, they're doing well!
I was thinking about this and I realised Martin makes similar points in the books. Unlike the show however, he's much more subtle. Martin spends a bit of time with each family's history, and in a lot of cases, he goes to the trouble to let us know which of those houses were raised above another by intervention of the Targs. Both houses Tyrell and Martell were placed above the houses that were originally the rulers of their respective areas. House Tully never had control of the Riverlands, and the Riverlands were not as they are today.
What I'm wondering now is if this isn't an aspect of the books that's gone mostly unnoticed or if this is just a product of the showrunner's imagination.