[SkyMarshal]

>I mean, the web is pretty much an application engine now and we're doubling down on the document metaphor? What?

I've been thinking similarly lately too. They're hardcoding semantics into HTML that may or may not change in the future. Better to avoid hardcoding things that could change or have subjective meaning whenever possible.

Instead, keep HTML tags simple and enable optional, flexible semantics via attributes and properties, along the lines of schemas (http://schema.org/). Let the internet standardize among schemas, and replace obsolete ones with new and better ones as they arise. Or, if it's not requirement for your particular app, just don't bother with it at all.