Originally posted by kraigg007 1) More focus points
Probably the least likely on your list, not only would it require a new processor (possibly a dedicated AF processor, which would be a radical change to the current system), but it also requires a change in PDAF hardware. The PDAF hardware won't fit both APS-C and FF. If it turns out that more than 33 AF points are needed to make significant improvements to the K-1's autofocus (which would mean better processing doesn't accomplish much without extra AF points), why not implement this technology first in a new APS-C body, where the Pentax line-up needs a boost the most and has the potential for higher sales volume than an upgraded K-1. There are more Pentax APS-C owners waiting for an opportunity to upgrade their camera body than Pentax FF owners. If anyone is unhappy with what the K-1 currently offers, they probably don't own one right now and are unlikely to buy the new K-1 just because it now has more AF points.
Originally posted by kraigg007 3) FF Frames Per Second Increase, 4) 4K video
These are both bandwidth issues in the camera's electronics and improvements in hardware to move more data from the sensor to memory should be transferable between APS-C and FF (possibly even MF) bodies. This type of improvement could also help implement future improvements to Pentax cameras and doesn't require changes to the image sensor or AF hardware.
Originally posted by kraigg007 5) 36MP is enough but a slight increase wouldn't be a bad thing
I don't see any reasonable scenarios where Sony can't or won't produce the sensor for the K-1 any longer, tooling and development costs are over and done with, the demand for large format (too big for smartphones) sensors isn't higher now than it was 5 years ago and Sony is looking for growth in its sensor business, not turn away paying customers. From Ricoh's standpoint, to buy newer, higher resolution sensors means higher prices from Sony and changes to other hardware to take advantage of the new sensor, in return for a relatively small number of incremental sales. The K-1 is still an upgrade for Pentax APS-C owners and going from 36 MP to 42 MP is not going to have a big impact on the number of buyers coming to Pentax from other brands.
The most likely changes to the K-1 will be improvements from the K-3II successor project that can be implemented right away with a minimum of changes to the other components of the K-1. The K-3II successor will have more changes and the resources required to implement all of those changes is what has pushed a K-1 upgrade to the front of the line.