I think they can really work on people who LD in-game. If you LD you should be able to rejoin where you were. Me and a friend were doing a co-op mission solo, 2 hours into it or so. We were just at the end when he got disconnected. Because of it I couldnt finish the boss and we had to restart. It would be nice if they put in a 5 minute or so LD so that people can rejoin... Even if it doesnt work in pvp or something. I cant see much exploiting with it, if you go LD you should stay in game for that long and you can still be attacked etc.
Sorry, just my rambling