H 1-6 header fonts, themes, and SEO

I notice that a lot of the themes use the H1-6 header fonts based on their size. But then I read that the search engines rely on these headers to prioritize searching the elements in your site.

Is it worth the effort to go through a theme and remove extraneous use of the H1-6 headers in order to ‘help’ the search engines find relevant material?

For example, the theme I’m using now included ‘Number of Comments’ in the H2 header font because it’s right next to the post title, which is also H2. For SEO, shouldn’t ‘Number of Comments’ be anything -other- than a header font?

If I were programming a search spider, I’d tell it to give up as soon as it found this sort of use of the header fonts, because they aren’t being used correctly. Which would be bad for me, because my best search text is at the H3 level below the blog title and the post title. And of course, the theme designer used H3 for the ‘Post a Reply’ prompt, while making the text I’m most concerned with plain old <p> text.

Thanks,

TW