I agree this could be a valuable training and critique tool for a department, but I think any department considering putting helmet cams in service should think about the liability issues that could result from bad tactics and noncompliance with SOG's. If the insurance company gets their hands on the video their attorney's could show that the department caused unessassary damage because of poor tactics and is liable for part of the repairs to the structure. Even worse a family could file a civil lawsuit against the department if your crews failed to find their child during a search.
There may be a way to keep this footage protected under "Peer Review", but you would have to consult your department's attorney.
True story: I responded to a single family dwelling structure fire at night where the fire started in the garage and was spreading to the rest of the house. Upon arrival I noticed that a power line had fallen on the garage and energized the metal garage door to the point that the door was glowing blue. I directed my crew to stop the fire from spreading past the garage, but to not spray water in the garage until the power company arrived and secured the power. The garage was a complete loss but we saved the rest of the home. About a week later I got a call from the insurance adjuster who aggressively question my decision to not extinguish the fire in the garage. While I believe I used the best judgement to protect my crew there are insurance adjusters out there who will question your actions and if they get a hold of a video of you fighting a fire you better hope you did the right thing!
As far as Chiefs are concerned, you guys better hope your department's fireground SOG's can hold up in a court of law based on accepted fire service tactics and strategies. If helmet cam video can be keep inside the department, Great! But if it has to be public record: Warning, Warning, Warning!