I recently started using ClearScope & SimilarContent. They're pretty good but Ahrefs just seems to do things better, so I figured I should request/suggest you make some content optimisation software!
No small feat, I know; but I'm guessing you've already got many pieces of the puzzle figured out.
SimilarContent Walkthrough Video - How to Write SEO Content: https://www.youtube.com/watch?v=8U44Qy9hX8s