I see no potential for a direct "K-70 replacement" … it's a well-specified camera with an array of features and functions far in excess of anything most DSLR users are ever likely to need … the development costs have been recovered, the design concept proven, just keep making the camera and taking a profit
A "KP replacement", on the other hand, as a mid-range gap-filler between the K-70 and the K-3iii is possibly a concept worth considering.
Call it what you like, KPii, K-90, whatever … a decision would have to be made as whether to continue the "different" appearance and ergonomics of the KP, or revert to the more traditional appearance with a built-in grip.
Keep the high-end prism for the K-3iii (unless they're actually quite cheap to manufacture!) to leave space for either a built-in flash or GPS, probably stick with the smaller battery to keep costs down, tilting or fully articulated screen definitely, various other features and options to be decided, including whether to continue with the "old-style" menu system or move on to that as used in the K-3iii. This last will probably be defined by which processor is used.
Whichever way it goes, I don't see myself needing/wanting a camera update any time soon … unless it's a K-3iv with a 36Mpixel sensor or a reduced function K-1 at a "budget" price.