I totally get that, and in fact have been on board with that idea myself. It’s not for nothing that I went for the size advantage of Micro Four Thirds. However, I will say that it is in exactly this same kind of conditions that I have come to the realization that the ONLY solution is to change the lighting. The easiest way to do that is with a small speedlight. Luckily, there exists now some very small and portable options (also affordable). Check out the Godox TT350 (http://www.godox.com/EN/Products_Mini_Camera_Flash_TT350S.html). It’s pretty affordable at about $85 on Amazon (here in the US),. You get the version that matches your camera brand, and it will take advantage of TTL (through the lens) metering, meaning that it’s a breeze to set up and use.
I think in this situation, even just mounting a flash on the camera with a diffuser or a bounce card and a warming gel to match the ambient lighting (so you can adjust white balance globally) would have really helped your subjects to pop, and allowed you to use a lower ISO for a cleaner result in the end.
I have resisted adding flashes, etc, to my setup because I just didn’t want the added complications of that. But I am realizing that if I “want the shot,” then under certain conditions you need to bring your own light. We all love post processing, but there is only so much one can do under adverse lighting in post.
EDIT: just a little example showing how using a small on-camera flash with a little diffuser can make an impossible photo possible. This is from our recent christmas fair here in my town, and was taken right at dusk, pretty much in the same (or even a little darker) conditions as you photo. Artificial lights abounded, so it would have been possible to take a shot in the ambient conditions. But I opted for fill flash so that my wife and baby would look like human beings, and not orange ghosts, lol!
Here is the absolutely un-edited (SOOC JPEG):