I've been going through an architectural photography phase and bought a Sony 10-18mm for the a6000. It will also work, with some cropping, on the a7. Unfortunately, I haven't had much time. I shot some test footage, which is completely ungraded and boring, but if you're interested in the field of view of the 10-18 on the a6000 then it should give you an idea.
Photographically, the 10-18 on the a6000 is a monster wide-angle solution. Great sharpness, contrast and color.
I did a little comparison with the GM1. The GM1 continues to amaze me with it's clean low-ISO footage. The a6000 is superb camera, but I don't think they'll ever get APS-C sensor as sharp as MFT in 1080. I think it impossible to completely fix the aliasing/moire issue with having pixels more spread out on the sensor, vs the MFT. What Sony seems to have improved is the chromatic aberrations, which is certainly the most annoying aspect of that problem. In short, not sure 1080 will get much better from APS-C camera.
However, I can get a shallower DOF with the a6000 that I can't get with the GM1. It's a tradeoff.
I have a Sony 35mm 2.8 which I hope to do some test footage with soon.