This isn't a great topic because there isn't any sort of trend here. 2008 was the first year the team was together and Rondo and Perkins were half the players they are today. And aside from the Hawks series, what was really that surprising? Going 7 against Cleveland isn't anything to hang your head about.
As for last year, you can't count it. KG was out, leaving us with zero front line. That's why the Bulls made it a series. If KG was healthy, we would've swept them.
Unless they struggle this year with a healthy team, I wouldn't worry about it.