"A decade ago the rise in popularity of Flash steered many web designers down the wrong path. It wasn’t the fault of the technology, but of the people using the technology. The same thing applies to HTML5: just because you can do something doesn't mean you should. I'm all for innovation, but innovation should not be regressive."

Yes. The first job of someone putting up a website new design or redesign is to do usability testing. Can a user who reaches your site by a search engine result or some friendly inbound link accomplish a relevant task upon reaching your site? If not, why not? As Steve Krug says, "this isn't rocket surgery,"

http://www.amazon.com/Rocket-Surgery-Made-Easy-Yourself/dp/0...

and if you aren't investing in making your website usable for users, related to some purpose you had when putting up the website in the first place, you might as well do without having a website.