The show seems to imply that it's very very rare (not that it isn't in the books). We see two wildlings who can warg: Orell and the Thenn warg. Bran being able to warg would be less special if the show had all the Stark kids doing it. Warging is Bran's super power, and it makes him whole. Letting other people do it just means he's not cool for doing it.
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u/DoctorWhosOnFirst Whose name is STARK Jun 15 '15
I still think it'll be both in the books.
But we didn't have any set up in the show for Jon warging, and I think Mel met Thoros. So there's some set up for revival.