When building a bespoke site a pet hate is that you start with a front-end layout that is semantically sound and robust, but when you try and create said layout as a theme in Drupal, by default the system adds
<div> markup around whatever node, field or general piece of information it can find.
The result is that I usually begin with Mothership as a base theme to reduce the noise of excess markup.
Will Drupal 8 (both core modules and shipped themes) adopt cleaner HTML semantics? If so, how might the new front end HTML compare to its Drupal 7 predecessor?
HTML5 is an obvious assumption. The game is no longer "wrap it in a div" as HTML 5 empowers front end developers to a wealth of possible tags in order to best convey meaning (e.g. aside, header, navigation). How will Drupal change to allow this new level of semantics choice to be controlled by developers?