Initially I was on board with the drop rate being too low. However that was before I learned it was just a one time step and not required for every weapon. Now I think it's fine where it is.
If anything it could add a pity system that if you go dry for 9 CE's then you get the 10th guaranteed per example.
For me I didn't mind the grind though since the atmas were secondary to lvling jobs in OC or farming gemstones if I did overworld.