This is a hastily updated version of the reduced mana calc using what we guess to be the new formula (Aura Reservation * (1 + Reduced Efficiency) / (1 + Increased Efficiency) = Final Aura Reservation). I make no guarantees that any of this accurate, so don't flame ggg or anything. As more information comes out I'll update the calculator.
I tried to follow what they said the changes were here. Items and nodes with a (?) are ones I'm completely unsure about and don't know how it's going to work. GGG seems to have removed more/less multipliers. The UI for this calculator needs a bit more work now to be more clear on the numbers (stuff that says its x0% is actually using 100% increased efficiency, the ui was originally meant for displaying the reduced mana stuff, I'll update it in the coming days). Also the calculator may break the health numbers when linking around aura setups, I have to fix that too.