I can see that this is not quite getting anywhere yet. Probably the best idea would to be to propose a title similar to "Embedded hardware and software" that would also imply integration and co-design. So the idea would be to leave electronics.sx for purely electronics stuff, i.e. PCB design, signal integrity, semiconductors, test & measurement, mixed signal simulation BUT excluding embedded software questions, HDL questions, co-design questions and large digital system desing question. Though there still seems to be an intersection, suppose one would ask about "What is [Insert the name of New High Speed Serial Bus]?" and the Q&A would flow in the direction of signal path aspects of using it because that would be the most important aspect of using that particular technology, however I suppose this is the same sort of intersection that many SX sites have anyway.
To me it looks like "Embedded hardware and software" would be also well suited for RTOS and Linux questions to, e.g. where it comes to questions about driver development, power-consumption optimisation and durability of flash storage using certain filesystem type.
Meanwhile, I'd like to point out that "Digital & IC Design" sound like a niche subject which could be covered by a tag rather then an entire site.