This is much better… it even follows the KISS principle!
[[html ...arguments...]] ... html code ... [[/html]]
There is no need to wrap content in an <html> tag. We should add all required HTML structure nodes automatically, even add some JS or CSS files, e.g. for automatic iframe resizing or to match the style of the content with the given site.
A real example would be then:
[[html]] <h1> My example header </h1> <p> My awesome paragraph. </p> [[/html]]