I've heard that complaint about Theon/Reek primarily on The Cast of Kings podcast. My take on that issue is that on the page it works that you don't hear from Theon for a while and its reveal that he was actually this tortured character Reek. Its like a oh shit moment in the book because you have been witness to this character's pain and the reveal adds the extra emotional layer.

In the show I think it was important to show the mental and physical breakdown of Theon though. The only option would have been to not have any of the Reek scenes up until last night's episodes because they can't disguise Alfie Allen. Same as with Barriston Selmy. And it would have been a leap too far for there to not be any scenes with Theon at all in Season Three either.

Some of the departures don't bother me that much. And I'll try not to spoil because I don't know where you are in the book but suffice to say that scene with the dragon and the follow up with the goat herder was kind of underwhelming.

Most book readers do get kind of possessive or up in arms when the show take liberties but I think it's all about the economy of storytelling. Those books are long and dense they can't exactly fit everything on the screen but this is the most faithful adaptation that I've seen. That court scene last night was freaking fantastic.