To release a 2.0 that basically is a 1.3 without some things is not much of progress. It will be interesting to see if they can complete new planned features without breaking the api when they move through more 2.x releases and later 3.0.
No, actually, there were quite a few new introductions between 1.11 and 1.13 (Glimmer, the new rendering engine; Actions and API changed, ED became 1.0, got more stable), and, as a result, there were numerous deprecations in the 1.13 release. 2.0 removes things that were deprecated in 1.13. Things like views, active model adapter, etc. have been extracted out in an addon.
None of these things broke the API; there was always a sane (although sometimes painful) process to help you through the upgrade. There are other things planned for the next few releases, such as routable components, new component syntax, etc. but the things they will replace (controllers and the old component syntax) will be supported through the 2.0 cycle (at least that's what's said).
Ember's deprecations in 1.13 were a bit of work for me, as a developer, but the new features in the past few months have done a lot of good to the framework and removed a lot of the complexity. I much prefer this way of upgrading, and I really, really appreciate the Ember team for doing it this way.
It's not a marketing release, Ember is simply following semantic versioning. Many of the new features that might've slipped into a 2.0 have made it into the last few 1.x releases, since they could be made backwards-compatible; e.g. Glimmer could've been held back for marketing reasons, but they pushed hard to get it out ASAP in 1.13 in June.
