TASERS, contrary to common belief, have actually resulted in less injuries to suspects.
The chances of injuring someone when going using physical force are much less
http://www.ledgertranscript.com/home/7864795-95/police-say-tasers-safe-and-effective
NOW....do people get TASED when it isn't really necessary? Sure.
But on the same token, do you think people get tackled and thrown to the ground forcefully when it isn't really necessary? Sure.
The whole concept behind the thing is to take a situation where you may have to wrestle and fight a person, and just immobilize them and allow you to handcuff them.
The concept is NOT supposed to be, "REspect mah authoritah! zapzapzapazap" when it's obvious you could have resolved the situation peacefully.