The biggest issue that I am seeing with the Siege LFR is that the vast majority of people ran to the Timeless Isle, grabbed all the 496 gear they could, and jumped right in. But the Isle does not have weapon/off hand upgrades, so their DPS is absolute garbage.
I inspected the nine lowest DPS on Nazgrim (Worst was doing 12k best out of the 'worst' was doing 40k w/4 Stacks of Determination) in the raid I tried to slog through last night. Out of those 9 people I would not even want to do a Heroic Dungeon with, one had a ToES LFR 2h, one had a MSV 2h, three had heroic dungeon weapons, and one of them had the 450 weapon you get from Arena of Annihilation.
I am not even sure how some of those people managed to get into the LFR, the math does not add up, but they were there and I will never be there again.