My first ~20 loot boxes were good, got 2 legendaries in my free one and 2 more (one each in 2 other boxes, but one was currency). But now I am getting 1 or 2 blue items in every box since 5 boxes ago and they are ALL duplicates. I still have about 30 blue items yet to unlock.
With this event making every item available, most people will have way too many of them left locked to even get close to getting them all even if they played all day every day.