It's actually a good thing they changed the infinite spawns. You'd get groups being incredibly abusive saying, "Don't kill the Lambs, farm the XP!!!!!" and then going on to be incredibly rude about it. What those rude players didn't understand is that if your party isn't lucky enough to claim the spawns, you get no XP from the kill because you won't be able to do enough damage to claim shared credit (die far too fast). So for the vast majority of the players participating in the FATE, it's worthless to sit and farm the Lunatics because you won't be getting any XP anyway (unless you have someone very good at claiming mobs and has an amazingly low latency).

It was a good change. Now you have to progress with it regardless.