Nice theory, but this is the bit that I fundamentally disagree with.
Forcing programmers to work in one particular style is usually not the
job of the language/framework/library. That should be up to the
programmer, or at least the local style guide. I do like your plan of
having identical interfaces to the same functionality (your example of
web-based and command-line is particularly appealing to my personal
tastes), but the same can usually be achieved with a well-built
library. In fact, all you need to do is have your model as a simple
Python module, and then the view and controller call on its functions.

What does your framework offer over a basic system like that?