I think that orbs of alchemy need to be a little less rare. I have played "The Soveriegn Slime" over and over, but I still have not got advanced orbs of alchemy, and it is hard to save up crowns to buy them off of auction. The orbs may be a bit, too rare.
Orbs of Alchemy
Try the arcade where there are boxes.
Getting people away from constantly running bosses is exactly why this system was put in in the first place.
My rule of thumb is to buy all orbs (from supply depot) up to 3* if I don't have enough from missions. I only farm 4 and 5* orbs since they cost too much.
And as zeddy said, just do arcade runs more often. In my experience, you get more orbs from the arcade than boss runs.
That being said, I do want Elite orbs to be found more easily. I have like 30+ eternals, and 1 elite.
I normally ran "Whipping and Mishandling" since one elite run gave me 2-3 elites. Now, I can't do such. They need to fix all the drop rates. I don't care if they're called rarities, just do it. And get these Warm FCs out of my stratum 4, I've passed the 666 mark already.
remember you can buy them from the supply depot (K is the default key). AH price for orbs is a little overpriced.
that being said, a little less rare should be fine.