Most of our larger clients now have editorial best practices to break content up with sub headers. Looking at sub headers tends to also help with analyzing competitive page structure (whether it be long form content to help editorial teams learn about what topics to include in a feature piece based on top ranked competitor pages, or analyzing related content modules and template structure, which often includes h3 headers.
If this was enabled, it would also be great to also do a count of the h2s / h3s, similar to what you currently do with H1s.
PS: Loving the crawler the more I use it. Thanks again for putting together another great product.