This part? I missed it the first time (maybe it was edited in later?) but I like this part.
Personally, I'd cap the amount dropped in some way that scales to the ship class / cargo space, possibly not in a completely linear fashion so pirating a T6 this way isn't a complete waste of time. Notably, it should always be preferable, imo, to use your words before your weapons when it comes to pvp piracy, even in an anarchy system, but being able to get at least some cargo from a runner would be great. Yanno, "makes no odds to me if you run or not, I'll get some cargo either way, but you'll probably prefer to just hand it over, savvy?"
Honestly though, the biggest problem affecting pvp piracy is the tendency of people to just log out, and if they do it before you fire a hatchbreaker they can do it immediately. Without an overhaul of the network model, I don't know what the best solution to this is.
I would like manifest scanning to temporarily place the target "in danger" for logging out purposes. A couple of minutes would do it - and make targets drop a big chunk of their cargo if they do log out while in danger from another player.