I predict (for what that's worth) that we are witnessing a secondary effect of Panasonic's emphasis on hybrid bodies.
Think about it. The S1R, S1, and S1H was basically a horizontal split. All three were pro-level bodies, each with a different emphasis in the stills/video spectrum.
Now we have the S1RII and S5II, both hybrid. If Panasonic were to introduce a third tier hybrid body - call it the "S0" - that was a true professional hybrid, we end up with a vertical segmentation, instead of horizontal.
S5II = mainline hybrid.
S1RII = "pro-sumer" premium hybrid.
S0 = true professional grade hybrid.
Give the S0 a 50 MP stacked sensor, a big buffer and true CFExpress write speeds, a bigger body & battery with better thermal management, timecode stamping and whatever else the video folks need, and I think both the pro sports shooters and pro-video people would be happy. Although I admit the anti-alias filter on the S1H might still be missed for video on a 50 MP sensor. Not sure about that one.
That could be a an excellent three-tier hybrid body system which forms the core of LUMIX L-mount.