I have been looking for a tool like this for so long. I used to use the paid version of SEO Centro, but they went offline a couple of years ago. My biggest hurdle was finding a tool that not only checked a box that you had an H1, H2, H3.... tag set, but actually displayed what they are. I played around on the demo site on their website and as soon as I saw the page analysis example and say my desired heading tags were listed I snatched this up. It's worth it to me for just that one feature alone.