I like the idea of a really modular camera system - just add the bits on that you want to use, or strip it down to bear minimum if you need a small system. For me, it just gives a few more options.
I like that too. The NEX EVF could be a bit more streamlined, I think, so that it wouldn't be so easy to catch on things. I have also looked at the Panasonic and Olympus accessory EVFs and they also stick way up and have designs that are not well integrated with the cameras. I think it wouldn't take much thought and work to make all 3 a bit less clumsy.