I'd just like to disagree with you on a couple points.

There isn't so much of a Bearshare black hole as there is a LimeWire black hole. Bearshare, as I have heard, still connects to other clients even though it does prefer other Bearshare clients. LimeWire on the other hand, doesn't seem to connect to many other clients at all unless you're an ultrapeer.

With a perfect Gnutella network, there would be no talk of blocking freeloaders and nobody would be required to share anything. I don't believe in shutting out freeloaders. They're just as much a part of the network as anyone else. Everyone's gotta start building their library somewhere.

Also in a perfect Gnutella network, there would be ONE client encompassing ALL great features from ALL clients, communication on the network would use a LOT less bandwidth, and firewalls would accept and pass Gnutella traffic by default.