Actually, that is not a bad idea, - having the M4/3 crop on the FF sensor and better still if M4/3 lenses could be mounted with an adapter.
The G9II and S5II already share the same chassis and OK, some bemoan the size over some of the previous smaller bodies, but actually with some of the bigger M4/3 lenses, they would pair up very well.
And if we started with something like a 61MP sensor, plenty of size to crop into for what would be what, something somewhere around 20MP I guess (based on knowing that APSC is 26MP).
I body, many lenses, so many different use cases...