The closer to the books the show stays the better it is. Even the latter books where Martin is starting to get tangled in loose plot threads have a clear progression of key characters and themes that sometimes gets cut or banalised on Game of Thrones.
I do think they've done a better job with some characters than I initially gave them credit for though. I rewatched the whole show 5-6 months ago, and even in season 1 there are a lot more clues that point to, say, Dany's sense of entitlement when it comes to power than I picked up on the first time. I think it confirms that Martin gave them a specific outline of where the massive players are supposed to end up, and why.