These cops should be given commendations. The plan A was to taze him. If that doesn't work, then plan B. Shoot him. Plan A didn't work, the K9 officer saw his partner about to get smashed, so he put the perp down. Job well done. For his actions, his partner will now be able to go home to his family.
As for the wieners who are crying about leg shots. Officers are not trained to wound perps with their firearms, they're trained to end the threat as quickly as possible. Shoot to kill. That is exactly what happened. They ended the threat quickly. And for that, they all get to go home to their families. Any firearms instructor will tell you the same thing. You never pull the trigger on someone unless you're trying to kill them.
I love happy stories like this.