It sounds like your engineering is to the point that most of it is essential complexity. Accidental complexity would be that your components are all tightly coupled to disparate areas of the application, and so when you go to integrate your new system, you find that you need to completely rearchitect large swathes of everything to make room for it, in the process causing a lot of strange bugs, because the code you rearchitected is doing a lot of unrelated things in opaque ways.