These are not the only changes, but they are the changes that affect most of the user base. The other changes are highly technical behind the scenes improvements and groundwork for SMT's. They don't impact users (yet), so most people aren't talking about them.

Actually, the highly technical/groundwork changes are the point of HF20. The curation rewards changes are a fairly recent addition that was not on the original roadmap for HF20 but had strong support for witnesses and were captured in HF20 because the coding/testing requirements were relatively light.