I don't think that it would be a good idea to change h2 -> h1
An h1 tag should appear only once in a site that is why it is usually used for the site name or logo.
An archive or category page would list a number of h1 titles which would result in incorrect html structure.
There is some evidence that h1 weighs less than h2 tags
http://www.sistrix.de/news/613-ranki...im-detail.html
Ben Pfeiffer from ranksmart.com
Keyword Use in H1 Tag
Not as important as it once was as a ranking factor, but still necessary on a well optimized page and very useful for organizing page content.
SEO specialist Thomas Bindl
Keyword Use in H2, H3, H(x) Tags
2nd most important on-page criteria (
weight changes every now and then and it can happen that h2/h3 have the same/higher importance than h1)