I see your point but, from my limited experience, I've found the material on decidability crucial to get a good working grasp of many of the core abstractions c

I see your point but, from my limited experience, I've found the material on decidability crucial to get a good working grasp of many of the core abstractions central to both complexity theory and theory of computation in general such as languages, non-constructive proofs, reductions, etc. I feel that without such exposure, it would be hard for a newcomer to appreciate the subtleties of the discipline... Big fan of your math \cap programming series, by the way. Keep it up.