Dark Souls has kinda made me reconsider my more lenient stance towards disconnects. I once had a match where I killed a phantom, ran up to the host, begin whacking him, and then BOOM he disconnects right when I'm about to kill him. When you get a disconnect from the host, you don't get any humanity or souls, which means that disconnecters are actually depriving invaders of both their time and winnings.
In the next souls game, I think disconnecting should at least give invaders the souls and humanity they would have gotten with a win. If the invader disconnects, it should give the host (And any summons) the appropriate number of souls and humanity. I don't think it should punish hosts (Because of possible connection problems), but disconnecting certainly shouldn't punish the people who didn't disconnect like it does now.