Upgrade to E-P5 or E-M10 mk II or GX80/85 or something else?

If you can, go out and see if you can hold each of the camera. That could dictate which camera you should go with. I thought they would feel the same but that’s not the case. The M10 Mark 1 felt too small and I had to use the optional grip. The M5 Mark II feels fine and felt off with the Fotodiox grip. The GX85 felt good but I had to adjust my grip to use the shutter button.

The IBIS does indeed make a difference on static subject (in low light or lower ISO) or if you have shaky hands. IBIS with electronic shutter can produce some very sharp picture. Another big benefit is when using long telephoto lens. It helps stabilize the image in the viewfinder which helps a lot with composing the picture.

I agree completely with the single control dial. Have dual control dial is great.

As for the VF-4 viewfinder, I didn’t feel it was better than the M10 or the M5 Mark II. I wear contacts and I can see corner to corner without any issues. I find myself using the Viewfinder a lot more when it was built in. Like you I felt the VF-4 was big and out of place. The GX85 viewfinder is like looking through a cheap telescope. It’s hard to find a good eye relief with everything nice and sharp.

The video is better on the GX85. People complain about the 1080P on the GX85 but I thought it was much better than the Olympus 1080P. I honestly feel you can’t go wrong with the M10 Mark II or the GX85.