I think they are doing an amazing job with the TV adaptation.
Long before Martin wrote GoT, his bread and butter was TV screenplay. When that was over, he was sick and tired of writing within those restraints, so he threw all of them out in GoT which was never intended to make it to any sort of screen.
Ironically, here we are, and the writers and producers have to figure out some way to adapt an unadaptable story - - a huge cast, including many young children, incredibly complicated storylines, a deliberately uneven pace, dozens of unique locations that play a major role in the political and military landscape, major characters getting knocked off left and right, lots of gore, lots of FX, characters who have deliberately obscure motives, characters who pop up at one point in the story and then aren't seen or heard from again for thousands of pages and so forth.
They've had to somehow streamline this story far more than LotR and get the jist of someone's character across in just one or two scenes that otherwise evolved through multiple chapters in the books. At the same time, they have to add expositions to get across points only slowly implied by the books.
Then there's the cast. They can hardly hire an actor to play in one scene this season, and then sit on the sidelines for two years. (Looks like they've already had that problem with Gregor Clegane).
All things considered, I'm really impressed with the product. But remember, it's an adaptation, and, by definition, it's not going to be the same.