This case is going to get dropped... gauranteed. He's calling the DA and Cops bluff and he's going to win the hand. If he's willing to duke this one out all the way, which not taking the plea deal essentially says, then I'm sure when it comes time to try the case, they're going to let it go and he'll be stuck with some lawyer fees.
I get tired of hearing people say that cops have such a hard job and they have to deal with a lot of weird situation. Well guess what, we pay an auful lot of money to have the right people hired and trained to handle those situations. If you can't take the heat, get out of the kitchen.
I went over this story with my 2 brothers, one who is a cop and another who is a lawyer and they both agreed the cop was in the wrong, but they'll never prove it. They both thought the charges would be droped, and the guy tased would get stuck with his attorney fees. Essentially, the department isn't going to want to risk the chances of losing the case when witnesses corroborate the accused story, the guy has no criminal history, and some of the witnesses have impecible credentials (unlike my spelling).
The main goal the DA and the cops had was to bluff the guy into taking the plea, and he obviously didn't. So know what will happen is the DA will fold and live on to go prosecute real criminals instead of trying the case, possibly losing, and damaging the reputation of his office and that of the police departments... its no good for them to even try it... but if they drop it, they'll save some face...