First of all, ross seals/shards mostly drop in ADQ on EE. People that ran ADQ EN and then the raid EE were killing their chances of getting ross. There was a nice 8 month window where drop rates were reasonable, but it's gone.
The drop rate of seals/shards was fine until U21 and now they are significantly decreased. I've seen the topic come up before but Turbine never addressed it. What I think happened is that Turbine inadvertently removed the seal/shard boost they previously gave. I ran ADQ EEx16 every week for 4 months and I can assure you the drop rate is about 1/5 of what is used to be prior to U21.