Quick word on circuit breakers. They are not to protect the box, but the power wiring to it. We are trying to prevent the wiring from setting a fire, not prevent the box from smoking.
On the E&E door. Are you folks (pilots) really worried about this? It would be simple enough to retrofit an electric lock controlled from the flight deck. Might as well do it to the 747's too while we are at it.
On someone entering the E&E bay and pulling breakers. I would hope that if someone was pulling breakers on an active system, you would get an immediate advisory message ( if not a caution) on the EICAS "ACARS MU FAIL" "TRANSPONDER 2 FAIL"etc
I would assume even if you were to send the FO to investigate, that would be worthy of a radio call to someone first?