The problem with a "GQ" is that the number of files shared (and thus the GQ) is determined in large part by bandwidth. Dial-up users might share 40 files (which is more than fair) and yet only get one upload per every 10 downloads. A T1 user might share 2000 files and get 10 uploads per every five downloads. The point is, if you have a slower connection, you shouldn't have to share as many files, and what's more people are less likely download any files you are sharing if someone with a broadband connection is sharing the same file. IMO, dial-up users shouldn't have to share anything to participate.
I think the best thing to do about freeloading is simply to design better clients. No client should allow a file to be downloaded to a directory that's not shared. Of course you could still move the files out of the shared directory after downloading, but I think most people wouldn't. Another thing that contributed to the high sharing levels Napster had though was its internal media player (since users would connect and share files just when they wanted to listen to their music). I personally prefer Winamp/XMMS (as do most developers I imagine) but that doesn't mean Gnutella programmers shouldn't outfit their clients with media players simply to promote greater sharing.

If you're connected to Gnutella through a proxy, I don't care what kind of hacker you are you can't figure out who the file sharer is unless you are the proxy machine (or compromise the proxy machine, which probably isn't possible for a simple Gnutella client). Not totally anonymous, but that kind of anonymity has little to do with hacking skill.