full frame look vs s35mm look for video

I have both the a7s and the a6300. I have been very happy with the look of the video coming straight out of the a7s standard settings (i usually dont have the luxery of time to deal with s-log etc).

I film a lot of interviews and all the highlights and the parts of a face that sometime end up a bit ugly and overexposed (unless you underexpose the rest of the face) on pro camcorders ten times as expensive with smaller sensors and even on the m43 cameras looks stunning straight out of the camera without having to go the s-log route.

Recently i bought the a6300 as an extra camera. Mostly because of the incredibly AF. It is a great camera in most ways and I know this is capable of producing beautiful video when using picture profiles with added dynamic range. But after using it just in the standard mode I just dont like the look. It is OK. But it reminds me a lot of the video you get from the m43 cameras. The highlights are OK but not beautiful and the picture just feels kind of "flat" and "dead". I feel like the result is similar on the a7s when using the crop mode. The look is very different from the full frame mode.   

Is this only because the a7s is a full frame camera with more dynamic range because of the sensor size and the a6300 is "only" super 35?

Or is it also due to the quality of the a6300 (which is much cheaper)? 

Do others experience a big difference when working with full frame vs super 35 for video?

Would love to hear other peoples experience with the two formats.