There is good information here.
Pentax K-70 Release Date, Price and Specs - CNET
My feeling is, the improved high ISO performance and probably I stop better IQ shooing at ISOs over 1000 makes the K-70 look good compared to a K-S2. Bu tit looks like to max out it's video capability you have to buy the new 55-300 to go with it. If you do movies it's worth a look. With 24 MP sensor and the new version of Pentax's PRIME MII processor which adds a stop of sensitivity , that combo could potentially surpass the K-3ii in IQ. Its definitely worth looking at in my mind.
The K-30 came out with AF features that were better than what were in there reigning pro camera, the K-5. Pentax in the past has often introduced features in their mid range cameras that were better than what their high end cameras had. So it wouldn't be impossible.
Of course to be sure, the K-3 replacement will be better than the K-70, which will in some ways be experimental, but when it comes out, the K-70 may well offer the best IQ of any Pentax APS-c camera.