I'm comfortable with the meaning of flagship evolving from what it was, into meaning whatever it is meant in the show. Meaning of words do change sometimes in radical ways. But I don't like the whole trope about the Enterprise D being the "first ship of the fleet".
As for blowing up the Enterprise or demolishing the Enterprise or whatever. It's just a crude way of ramping up the drama and making whatever movie or episode it's featured in exceptional. The Enterprise-D gets blown up alot. Q-Squared, Cause and Effect and that episode where the 'prise is frozen in time are but three episodes off the top of my head.
As for blowing up the Enterprise or demolishing the Enterprise or whatever. It's just a crude way of ramping up the drama and making whatever movie or episode it's featured in exceptional. The Enterprise-D gets blown up alot. Q-Squared, Cause and Effect and that episode where the 'prise is frozen in time are but three episodes off the top of my head.