Well, I have to admit that I have a tough time believing that fascia stretching accounts for growth. If the stimulus and response for growth is there, the membrane that covers the muscle fiber is not going to curtail that growth. There's no way in hell that a pump could make it stretch while growth at the molecular level could not.
And even when not specifically setting out to get a 'pump', every workout I do results in a pump to one degree or another, so I don't see how training specifically to get a more pronounced pump is going to omprove response by an appreciable amount. If that were the case, then why don't you see guys with disproportionately large lower back areas? Extreme lower back pumps are commonplace among AAS users, yet I've neither read about nor experienced any pronounced grwoth in this area, which would indicate to me that there isn't much benefit that results specifically from the pump.
True, heavy singles involve the nueral system heavily. A good way to sidestep that factor would be to do multiple sets of, say, triples and get the desired muscular effect as well as going heavy. You get the best of both worlds - heavy weights and muscles that ge lots of work. BTW when I say 'work' I mean weight on bar x number of times lifted.
And explosive movements are fantastic for growth - the amount of force/power they demand will stress the muscles AND the nervous system. Yes, exposive lifts heavily involve the nervous system, but it's not as though the nervous system can perform actual mechanical work. That task still falls squarely and solely on the muscles. Ever seen the traps on an Oly lifter?
Still no sale on pumps being relevant. There are lots of people (myself included) who give pumps no heed and are none the worse off for it. Increasing poundages on the big lifts matters. Eating appropriatley for your goals matters. Drugs matter. The metabolic side effects of lifting, trace mineral intake, meal timing, etc. do not. Powerlifter, bodybuilder, Oly lifter, it doesn't matter. Muscle is muscle. It gets stimulated by doing work. It grows by being fed and allowing for recovery. THe further one gets away from that, the more their wheels will spin.