I'm not sure what the complaints are about- the best "live" albums in metal history are mostly studio productions:

Tribute (Ozzy), Alive (Kiss), Unleashed in the East (Priest), etc.

I think Live After Death was relatively untouched. Still, the point of a live record isn't entirely to have "live" music, but to have music that reflects the electricity and energy of a live show. A lot of music (c.f., Y&T, early Priest, etc.) just doesn't come alive until it's played in front of people.