What they ought to do is build a camera and mike into every taser, that starts recording whenever it is powered up, and which security-locks the recording when the taser is fired. This wouldn't cost much. This should guarantee that cops use them only when they are seriously threatened or assaulted by violent people, because there would be no chance of getting away with tasering people merely for being lippy or awkward.

With that precaution in place I'd be willing to see every cop carry one if the cops think that they need to. It's probably less dangerous to be tasered than to be hit hard with a baton or truncheon (and batons don't have cameras in them to record their usage).