1. No battle between Oberyn Martell and The Mountain
After HEAVILY teasing a big epic fight between the sexual vengeance-machine Oberyn "The Rad Viper" Martell and The "Gregor Clegane" Mountain, the show didn't even feature either character. Stretching things out helps up the tension, but it would have been nice to get some resolution on that.
2. Way too many new characters and locations
Wow! As if there wasn't enough characters and plotlines before, now we're getting all this stuff about far off city of "Nuyorke" and Mark Ruffalo as an enigmatic new player in the political landscape of Westeros. Confusing much?
3. Mysterious new disease comes out of nowhere
Seems like George "Arr Arr" Martin is running on fumes - suddenly there's a new disease that came out of nowhere, that's going to heavily affect the rest of the series. There weren't even hints of this before, and now it seems like it's the big plot thing. Get back to the dragons!
4. So many changes from the books
Uh, where to even BEGIN with this? Even with the heavy focus on gay characters, none of the confirmed gay characters from the books showed up (Loras Tyrell, Renly Baratheon, Freddie Mercury). Plus, none of the characters given focus ever had POV chapters in the books (unless they did in books 1, 2, 3, or 5 - technically I only read Feast For Crows). Really weird adaptation choices, frankly.
5. Awful accent work
Nearly everyone attempting a British accent (the standard for Game of Thrones characters) utterly failed here. Pretty much every character in Nuyorke sounded like they were from east of New Jersey!
6. Bizarre crossover with The Big Bang Theory and The Avengers
So for some reason Sheldon from The Big Bang Theory and Bruce Banner from The Avengers were there. While I like the idea of Game of Thrones crossing over with other universes, I think this should have gotten some more explanation. Oh well, maybe next week.