Shows like Rome, Deadwood, and Boardwalk Empire on HBO, and then shows like Shameless, Californication, Spartcus, among many many more on other networks, already shattered all of those boundaries. Game of Thrones just took it into a high fantasy realm.

When you talk about violence, well then, they upped the game a bit. But even then, not that much compared to some of the one listed above, like Spartacus. The books are also significantly more grotesque in the violence and gore than what you saw in the show. So even then, they kinda pulled their punches a bit.