So far it seems like Meteor is focused on data syncing and live UI elements. That's neat when done well, but the main pain points for client-side heavy apps is the mismatch between the server and client and between the traditional URLs structure of web pages and the MVC structure of apps.

I'm looking for:

* Complete parity between server and client-side rendering for content. This is required both for first-page performance, caching, and SEO.

* URLs as the foundational organizing principle of the app. The mismatch between clicks, back buttons and external links makes code hard to organize and apps behave strangely without serious work.

* Database agnostic. Relational datastores remain incredibly productive and proven for the vast majority of apps.