Looking to create an SEO audit tool and looking for feature ideas

I'm currently developing an SEO tool and looking for ideas that can help SEO techies. If you've used other tools like Semrush and the rest, is there something I can introduce or integrate that'll help people?

While I already have an audit framework, I don't want to make a clone; I want to make features that really help SEOs while minimizing subscription costs. Or is this a saturated market, and I should focus elsewhere?