Yes, police went too far because they are meant to protect people, not shoot them. Shooting should be a last resort, but it does not appear to be the case here. They simply were afraid for their lives so they took the easiest way out, firing a gun at the victim.
Police officers have such a dangerous job, but I would hope that most would try to disable rather than kill. The motorcyclist wasn't armed, and although he was said to have been driving erratically, witness accounts differ pretty drastically from police as to whether he was aiming for the police car, and as to whether or not the officer who shot him actually got out of the car. If the officer shot through the window, and Sterling didn't actually try to ram a vehicle, they went too far.
The police definitely took things to an extreme when they responded to the situation in Washington, D.C. We can add this to the list of instances where police have felt that they have enough power to use more force than is truly necessary. Indeed, when I ran a search for this incident, too many similar results came up, which indicates that the police have gone too far time and time again.
Police in the United States have become trigger happy. Everyday there are more and more stories of police related shootings where th victims were unarmed and tried to comply with the instructions. The US is getting closer and closer to becoming a police run state and this will bring terror to millions.