I agree with Pedro Pascal's portrayal as Oberyn being super awesome. He's everything I imagined him to be like. Just a shame they didn't elaborate more about his reputation as a deadly fighter. Makes me keen to see the revelation of the Sandsnakes
That fight is gonna be awesome and at the same time really sad when his character is killed off. For me, that was one of the most amazing parts of that book and personally got me too invested in the character...
As for the Bran-Jon-Craster's Keep change in the show, I actually didn't like that. As others have said before, it diminishes the pains that Jon feels not knowing whether the other siblings are alive, and Bran's pain in not being able to reveal himself.
Lots of things that the show's direction takes that pretty much just highlights the insignificance of certain arcs in the book. Take for instance Crow's Eye (the Greyjoy brother)... he is never revealed at all thus far, and you wonder if his quest to woo the dragons is at all important in the book...Likewise with ColdHands. And they are taking far too long with the Castle Black storyline...