How much would it break things if I were to move the banes and boons system over to Dime Adventures, thereby changing the skills, but nothing else? I am terrible at mechanics, so are there any other tweaks I'm overlooking that I'd need to make for that to work?

The boons and banes system should port over easily enough, either as a replacement for circumstantial modifiers or as a full skill replacement along with the Age of Ambition-style skill ranks.

Let us know how it goes!