Man, this is a complex subject. Regardless of any individual skills an officer has, they have to fit within the realm of accepted Defensive Tactics in that officer's department....or city...or state, whatever. And regardless of the Martial skill of the DT instructor, his teaching has to fit within those same parameters. The problem has always been time. How much time is devoted to the teaching of DT. Which is so small it's scary. Defensive Tactics is a neccessary liability to all departments. And many of the programs are built for the convience of the DT instructor as opposed to the actuall needs of the officers.
I was originally hired as a DT instructor, but I had to go through the same academy process as everyone else, including DT. Which was taught to me, I swear to God, by an auxiliary officer reading from a book as he taught. And he did not read well. I remember thinking, "My God, I've died and I'm in Martial Hell."
Here in Massachusetts, we used to have The Massachusetts Criminal Justice Training Council, (now defunct) which certified all DT instructors. We used to get certified every two years. Some of the folks I met from around the state were guys with no background in police work and no background in Martial anything. Several of them confided in me that they had never been in a fight and hadn't actually made an arrest on a resisting subject. (I know what some of you are thinking - that couldn't be - it was) Yet, they took a weeklong course and were now the shiny new DT instructor for their department.
That's why I say I have no idea which Art might be best. I think Ballen is spot on - Verbal Judo.