Version 22 was shown at IMTS in Chicago. The resulting feedback was nothing but positive. Here are the answers to your questions below:
1. Yes. The system offers an associative job tree and a lot of new functions geared toward automation.
2. Yes. All of the modeling, geometry construction and surface creation features in V21 are still in the system as well as other features to speed up design. The system is fully OpenGL so that you can draw with solids rather than only view a wireframe of the solid.
3. Yes. STL has been added.
4. Posting has been vastly improved and does not require scripting. Post can be defined by the user.
5. Yes. Several hundred.
6. There is new simulation and verification added that is superior to the V21.
7. RS 232 has not changes.
8. Right now there is no support for OpenAPI applications or scripting.
Hope this helps.