For example, Vue 2.0's announcement[1] made clear that the release was about performance, new render functions enabling new component-based patterns, and server-side rendering.
What's going to "wow" Vue and React users who haven't looked at Mithril?
[1] https://medium.com/the-vue-point/vue-2-0-is-here-ef1f26acf4b...
Otherwise, the "big picture" hasn't changed since the v1 release. Mithril is a lightweight alternative to those frameworks that provides routing, auto-redraw, closure components, XHR utilities, reactive streams, and a testing framework out of the box. The v2 release has less to do with gaining market share or generating hype than it does refining an already great tool.
That doesn't seem to be covered by the release announcement, but is addressed here:
Prior to this release, the Mithril team went through painstaking troubles to release RCs to help consumers prepare for the breaking changes and find issues before the official version bump. Now that the code is deemed stable, the 2.0 milestone simply formalizes that the major version bump is now official.