I would like to be able to change the default fill opacity in DI i.e. set it like a preset, or to be able to set it for more than one layer simultaneously.
I spend lots of time changing the fill opacity in order to see through a layer or to find out if there is overlapping.
Frankly said, I don't know when I really need 100% fill opacity ever.
That said the simplest solution would be to change the default fill opacity permanently to 50%