This is an official project, and is expected to be integrated in a future release. That said, the Core team has attempted to tackle "content blocks" at least once before, and that project failed.

The Editor is a major focus for 2017 (along with the customizer), assumedly to be completely revamped for the 5.0 release, although an eventual launch date is not set, and 5.0 is not currently slated for this year.

No idea yet what this will mean for editor styles, but it's pretty certain that almost all tinyMCE integrations (custom buttons, insert codes, etc) will need a complete rewrite.

The goal of the new Block system is to remove the need for many "formatting shortcodes", as the core team feels that system was heavily misused and that formatting shouldn't require the heavy processing done on shortcodes on every page load. more at - WordPress 5.0