I really liked the 2nd episode as well, but I did notice a few differences from the book this time. I didn't notice any in the first episode. Nothing that was changed really took away from the story so I wasn't offended by it.
Joffrey is a wimp, but from the books I gathered Viserys was more of a spoiled, temperamental brat than a wimp. He's vicious and feels entitled, but I don't feel like wimp is the right word for him. Both are despicable characters.