In response to the publishing of the HTML Design Principles Gary McGath asks:
What bothers me most is that the document doesn’t say anything about why there should be an HTML 5 at all.
Simon Pieters, from Opera Software, answers:
Specify how existing text/html documents are to be parsed and processed, so that a browser can be created from scratch in the future when the source code of concurrent browsers are lost and the world has moved on to some other format. Implementing a browser based on the SGML, HTML4 and DOM specs will not result in a browser that can render most of the Web, because they don’t reflect the Web.
Increase interoperability between browsers so that authors don’t have to use hacks or workarounds for things to work as intended cross-browser, without having browser vendors being forced to reverse engineer each other.
Have browser vendors come together and discuss things they want to implement (like video), instead of having browser vendors implement new stuff in incompatible ways (like in the IE4/NS4 era).