Personally, I'd really appreciate the extra digital zoom capabilities, but for shooting 1080p (as I do) the 6K sensors are just as good and most cameras don't give you the digital zoom options that I'd really like, so the resolution of the sensor is secondary in that sense.
Also, if the battery life is crap and it overheats, then it's giving me zero footage rather than even sub-optimal footage, a pretty fundamental issue.
The other issue is that if you're using the sensor to get a 4x digital crop (1080p --> 8K) then your lenses will be by far the limit to the quality rather than the sensor. You might find that a 6K sensor upscaled to 8K has the same level of fine detail as an 8K sensor without scaling.
Assuming you have a fast enough machine. Many people would argue that any decent machine can edit 4K, but with many cameras shifting to IPB, 10-bit, h265, decoding that footage in real-time is no small feat at all.
If I end up with a GH6, which lacks the 2x zoom function from the GH5, then I'd probably just program a mode to be 4K 1:1 and swap to that and then crop in post. Hardly ideal, but would give me a bit more reach and still be downsampled to 1080p.