Part of the problem with Echolink in specific is that too many node  
operators (who have their nodes connected to radios, by the way) run  
just plain sloppy nodes. They let courtesy tones, ID'ers, noise  
pulses, and all manner of things go out over the network, which just  
makes it awful for anyone connected to that node, especially if that  
node is on a conference. Some tightening of standards (something more  
like what you might find in the IRLP guidelines, though perhaps not  
quite as anal, maybe) would probably not go amiss.