The announcement of the Panasonic S series is a complete acceptance that smaller m4/3 sensors are not the future but the past. As now Canon, Nikon, Fuji, Sony, Leica and now Panasonic have shifted priorities to Full Frame Sensors as mirrorless has allowed the smaller form factor without compromising low light performance and absolute stills image quality. Fuji is also going strong on Medium Format stills oriented cameras like the new portable GFX 50R which meshes a rangefinder camera with a huge MF sensor.
The move by Panasonic, which had been leading in mirrorless frame rates in continued recording with their Lumix GH5 and GH5s Series up to 240fps 1080p, will now focus on larger sensors that produce more heat and may be much slower to read at high speeds. Sony has so far been able to only have 120fps 1080p recording in their a7 series for example. If the Panasonic S1 at 24MP can only do 120fps 1080p which is still unknown, it will not bode well for slow motion frame rates for some time.