I'm going to speculate that tasers have not reduced the death rate by much. Sure there are some instances where an officer loses control of a suspect and ends up getting killed. However, my guess is most officer homicides are instances where the officers should never pull the taser instead of the gun. I'll use the recent Ogden slaying we discussed as example.
In my reading, based on stats that are a bit old, there has been a drop in the number of deaths of police officers after they started using tasers. To be fair, they have also been using tasers quite a bit more lately which increases the number of issues with civilians even if the percentages stay the same.
I more or less agree with your entire post except this part where you fail to condemn the officer for making a terrible decision. There was nothing split second about it. This was a very routine part of an officer's work and he was well prepared to make a better decision. If this were anywhere close to a questionable decision, and it was not, then I would back the officer 100% by giving him the benefit of the doubt.
If by condemn, you mean give him jail time, then no I don't condemn him.
"neither do I condemn thee: go, and sin no more".