Using George Zimmerman and officers that used deadly force in potentially hazy situations as evidence of your argument is, to me, a bit suspect. I don't agree with what Zimmerman did and while I don't think he was guilty of murder, I think he could have been found guilty on a lesser charge, but the DA overreached. What we see in the media most recently are private cell phone videos showing only small segments of what happened. The media uses this to sensationalize an event. Dashcam footage can crucify an officer and can also vindicate him/her. Unless you have a breakdown of the exact percentage of when it did which all we have, on my side too, are anecdotes.
I'd also point out I'm talking about defending yourself in your own home where the legalities of defense are often different and the chances of being recorded by passing strangers seem pretty small. I do think there's a difference between audio and video recording and remember I said audio. And yes a bad shoot is a bad shoot. If you're in the wrong you can likely end up in jail.
As for waiting til everything is over, you're betting on being on top and in good shape when it's all over. Train and trust to luck that you will be, but if not then having help already on the way isn't a bad idea. Maybe you'll be dead when they show up, or maybe you'll be bleeding after the fight and can still be saved. You're also banking on the other guy being dead and not having to dispute what he claims in court. For that matter as a guy with 25 years experience you know that "Johnny was a good boy" to someone, so a civil suit will come too. Having a recording where what I detailed above can be heard can potentially help you there as can having a record of calling the police as the event happened (even if you know they won't make it in time it's evidence of trying to get the "proper authorities" involved). But like you said, it's an individual choice.