I'm looking at Mother's first drop records of when a 14 star weapon has been dropped on PSO2NA, compared to the first drop records from Mother on PSO2JP. Also note, these aren't the Trigger records.
I also kept note of the Deo weapon drops, just as a secondary reference for drop calculations.
And now, thanks to a friend of mine who caught a picture of the earliest records of Mother from PSO2JP, we can see what the drop rates were like on it, and hopefully compare the records.
First off, let me do a calculation of approximately how many runs of Mother it took on NA for there to only be 1 Kazami no Tachi drop. I'll use the Deo drops as a reference. Between all Deo weapons, there were an average of 36,000 dropped. There are 17 weapon types. This would make ~612,000 Deo drops on the records. On a personal average, I end up ex-cubing roughly ~30 Deo weapons on an average Mother run. So how many runs of Mother is this record showing? Roughly 20,400 by those calculations. In all these runs, Astra has only dropped a total of 96 times (~0.47%). I should also note that I don't always get a Nox drop from Mother, so I can't reliably use Nox weapons as a reference for calculations to compare how many runs... though it's also all I have to go off on with my image references.
On PSO2NA, I would say there were an average of 300 of each Nox weapons, with 17 weapon types, making the total 5,100. The drop rate for a Nox weapon drop? That's about 25% chance that you'll see any Nox weapon.
Unfortunately, I do not have a proper approximation for how many runs this PSO2JP record show, though I'll round the number of Nox weapons to 900 each, therefore making 15,300 total. The only close comparison I can make are the Astra weapons, which 2,025 dropped.
Oh yeah, an odd thing to note, it seems Redran Egg 13star seems to have the same rate in both NA and JP... though that's more of just an observation based on data. I assumed more people ran the first few Mother in JP than in NA. (19 in NA, 31 in JP)
Anyways, with the Astral and Nox records, I can make a comparison of their drops.
NA | JP 5,100 | 15,300 (Nox) 96 | 2,025 (Astra)
So alright, something seems a little different here... but I'll compare the drops of NA weapons first. For every 5,100 Nox drops, there were also 96 Astra drops. Astra drops make up ~1.8% of Nox drops.
Let's compare to JP. For every 15,300 Nox drops, there were also 2,025 Astra drops. Astra drops make up ~13.2% of Nox drops.
That's strange. It's as if the drop rate have been nerfed in NA; like they added an extra 0 somewhere to their drop rate to make it worse than it ever was initially in JP. Heck, the drop rate for Nox probably isn't the same for NA as it is for JP, and sadly I have no evidence showing that. HOWEVER, the difference in rates is significant, and there's no reason why it needs to be this low, ESPECIALLY since we're rushing through content all the way to Episode 6, which we'll have trade-in 15star weapons. Astra weapons are trash compared to Nemesis/Slave weapons, which have been available since PSO2NA released Ult upon the Win10 release, and they're a whole lot easier to farm than trying to get anything of value from Mother. Also, only seeing 1 14star weapon drop from Mother on NA is painful to see; it's like Spread Needle and Eternal Psycho Drive may as well not even exist, so sadly, I can't even really properly compare the 14star drop records.
Sega, please fix your drop rates. When I've run 30+ Mothers, and no Astra weapon has dropped, there's a problem here; especially when Yamato seems to drop its 13stars every other run for me. These drop rates were low enough initially on JP to account for the fact people will be able to run Mother over and over for the course of a few months before the next major boss raid released; just to keep some hardcore rare drop enthusiasts playing for a long time, and yet, we may not even see a scheduled Mother 1 month from now (at least of this particular UQ). It would have been nice to be able to run multiple Mothers triggers, but with the Fresh Finds shop down... I guess I'll reserve my SG for now.