This is a non-issue. The only way this argument holds any weight is if the search engines ignore the new HTML5 tags, which is preposterous. Does anyone actually think that Google's search algorithm which looks at over 200 factors including such on-page nuances like keyword proximity, phrase groupings and even parses Flash for hyperlinks is going to ignore the new HTML tags?
There's no way that any of the search engines that are worth their salt will disregard the fact that an <H1> tag is wrapped in <aside> tags or <nav> tags or whatever when it comes to assigning significance to that string of text.
As a commenter stated below, HTML5 is a moving spec, so yeah it's risky to implement this approach now. However, by the time HTML5 is released it's a certainty that the new tags will enhance the search engines' understanding of page content. It will allow us to signpost the hierarchy in a more nuanced way than 6 levels of header tags.
This title is link bait in the negative sense of the word, i.e. it is not supported by the content that follows.
TLDR; this guy doesn't know what he's talking about, the HTML5 spec will be better for SEO.