Of course lots of common plugins would be expected to be included with the default installation, especially the form designer.
The distinction I'm really trying to make is: certain things are core low-level features that have to be programmed in a platform specific manner for each kind of device... because there is no other way. Everything else can be a plugin which can perform its duties on top of that layer. So if someone were to make some workflow specific plugin, they do it once in a generic manner, instead of making one for Android devices, another for PCs, another for websites, etc.
I realized I didn't really answer your question. The core functionality is stuff I must get in place to enable everything we talked about. The overall vision of the system has not changed from previous discussions... I'm just zooming in on the nitty gritty details of the implementation to try and keep everyone in the loop. It's the divide and conquer approach!