At first, like everyone (I think) I saw the specs, the price and thought..whoa! Makes my recent GH5s purchase very expensive (but I still got it for a super low price, so can't complain...)
But here and on other forums I visit, people are starting to see the drawbacks of the battery, recording formats and the additional accessories you need to get it up and running.
Underwater, we have the issues of:
1. Battery life (only real option is USB based pack inside housing, like the A7 but means bigger housing)
2. Screen position
3. Control access
4. Heat (so might need fans, then an increase in housing size to cope with additional hardware and NPF battery)
As to whether or not it will get ProResRAW, that will be complicated issue, as its a licensing issue, only DJI and Atomos (I believe) have acquired ProResRAW licensing for their devices at the moment. So if they managed to get it on there, it will probably be a V-LOG-L type activation, or back to base upgrade as the licensing is per device.
Looking into the future, I can say that my 'next' camera (whenever that will be) will have to have ProResRAW, to make me wanna upgrade, it looks an amazing advancement in the < $5000 category.