Wow, that's really amazing! Great idea to add a screen for the buttons. Keeps the interface minimal but usable without menu-diving. And I think you've improved a little on my woodworking joinery as well 
The push encoder thing is a good touch, tweaking the morph knob to select was always a little hackish.
Have heard good things about I2C but still stuck in my serial ways for the most part - I can see why the switch makes sense. I'm sure people would appreciate seeing your patches to see how you've implemented it as well.