Quite interesting thread. I think it could be good to make the fundamentals absolutely clear - Powerplay is in it's core, a Player(s) VS Player(s) system. NPCs have no impact on it, neither is it in any way random like BGS is to a degree. That's objective.
Now, for the subjective part. I would say if we logically approach this fact, we do have 2 options - we either say well, lets make it simple, whichever group is stronger in the Quantity X Quality ratio should have the advantage. This imo feels like the most fair system because we reward both parts of the equation.
Alternative to this is to say well - we don't care about the player skill part of the equasion.
Personally I think this is much more boring in the long run and not as rewarding for the veterans and even with all the changes... We are essentially back to braindead "who can outhaul who"
In regards to NPC's, you're correct.
Power Play is a player-driven system, however, at no point does it require one player to shoot another player.
A player in Solo Mode can "combat" another player in their Solo Mode via the Power Play system.
So I wouldn't call it a "PvP system" as that expression has certain connotations that you'll be shooting and shot at by other humans.
And other humans are completely optional in every aspect of Elite Dangerous