That's my problem, too. I keep thinking, "Hey, that's WRONG!"

I've found that's it's best to think of them as two entirely different things.
I think you have to start thinking of the show as being
based on the books, or the characters
inspired for the show, not a
re-creation that follows the books faithfully.
When I was a child and could order books in school through Scholastic, after seeing the movie,
The Sound of Music, I went & ordered the book,
Maria von Trapp's life: her Sound of Music. (Or something like that.) When the book arrived, it was NOTHING like the movie. It was her autobiography. I hadn't realized at the time, what I really
wanted was the actual play or script from the film, to re-experience and read the dialogue from the film.
If people are picking up the books, hoping they will be the show, they WILL be dissapointed.

Some things written just don't translate onto screen well. Some dialogue, when read, really do not work actually coming out of people's mouths. That's why playwrights have play readings. To hear what the dialogue sounds like actually coming out of people. Some scenes & plots that move on the page are dead on screen.
In the end, it comes down to money, business & ratings. What will move the TV show? I think if HBO wants this series to continue, and it does have the old
Sopranos time slot, anything in that slot has to try to get the ratings
The Sopranos had for many years. The show will
have to deviate from the original books. It needs story lines that will reach a diverse audience, not just vampire genre fans.
It also looks like this show is more of an ensemble show, that 2-3 character driven, which is why they are highlighting more characters that are minor in the books.
I am a die hard
Star Trek fan. The latter 4 series are only
based on the original series. And the latter 3 were hardly based on Gene Roddenberry's original vision of the future, at all, once he died & Rick Berman took over the helm & changed the vision & concept of hope for the future to one of conflict, bickering and a darker future.

In fact, the last series,
Enterprise, so lacked Roddenberry's vision, it tanked and ended the franchise.
IMO, the best of the latter series was
The Next Generation, because it was an
ensemble show.
TV shows which last are ensemble shows. Shows where one or two of the main stars leave, the show still continues, like
NYPD Blue, Law & Order, The West Wing, M.A.S.H.
Again, if Sookie & Bill fizzle in real life and the actors can't keep the fizzle onscreen, the show may move towards a Sookie & Eric storyline, or something way, way different from the books.