I think the best solution here would be to enhance the capabilities of custom Daily Deeds to match the hard-coded ones. I’m thinking ASH script hooks along the lines of the counterScript system: you specify the path of ASH scripts that act as triggers, and the path of ASH scripts that actually get run, and they each have designated functions that get run.
I’d also welcome better organization options for Daily Deeds, where you could group multiple Deeds together into one collapsible section of the Daily Deed list. Bale’s script linked above is an excellent illustration of why this is necessary. Comboboxes are a step in the right direction, but without the ability to nest or combine choices, they can only do so much.