Pixel size a7s

[64mulford]

I think I read somewhere that one reason the a7s is so good in low light is because the sensor has larger pixels. This also means less megapixels overall so not highly rated for photos(if you think megapixels matter). I'm a m43 shooter so my question is could this technology be adopted to say the gh5? Give it less and larger pixels to give it better low light performance? Or am I wrong?