It's always seemed to me that the DF rolls out a mix of jobs unless there's no other option. I've almost NEVER seen the DF roll two of the same DPS in a 4 man group. Not that the LB nerf will affect 4-mans too much since only the 2nd and 3rd bars will be filling slower and you only have bar 2 on the end boss. I'm still of the belief btw that the LB rate will be tied to the party stat boosts so say stacking melee DPS with no BRD will keep your DEX light from activating or 2 WHMs causes the PIE light not to turn on. It won't affect tanks because both tanks activate the VIT light. Double stack BLM with melee and a BRD and you're good because you still get DEX INT and STR. 4/5 lights probably wont have much of an effect, but if you only get 3 you'll feel it.