The Panasonic GH5 camera will not feature a Super35/APS-C sensor
Here is a video recorded last week at the 2016 NAB show where Panasonic representative confirms (at the 5:44 mark) that the upcoming GH5 will remain a MFT camera and will not have a larger sensor (Super35/APS-C sensor):
The question was based on the JVC GY-LS300 camera that has a large Super 35mm sensor inside a MFT mount.
The Panasonic GH5 camera will most likely be announced at Photokina in September.
Thanks FT!