Looked through the stats on the camera.. I kept saying.. wow.. that's great. Holy cow.. that's fantastic.. then I got to the buffer.
7 frames per second.. love it! But it's only good for up to 8 Raw / 28 JPG.
I was likewise impressed, mainly over the ISO capability till I read further. It's been a learning curve on the K3II but now that I've had time to get used to it, I'm mostly happy. The K3II features ISO up to 51,200 vs the new KP 819,200, but frankly I've never had the need to even get close to the maximum on the K3II.
Resolution on both is the same 24.3, with an APS-C sensor. The KP features the 5 Axis SR II vs the SR on the K3II which would be nice, and the KP features the updated CPU Prime IV vs the Prime III in the K3II, both of these would be a nice addition, though again not enough to warrant me to upgrade.
One thing I found misleading was on shutter speed, the mechanical shutter only goes to 1/6000, to get the 1/24,000 you have to go to the Live View (screen) mode. Pentax AF uses Phase Shift in the view finder which works great in low light, the Live View screen uses Contrast Detection, which can really hunt a lot in low light. The K3II features up to 1/8000 on either mode. The other biggy they aren't making much notice of is the KP, is at present, only rated for 100,000 shutter clicks vs the K3II's 200,000. You mentioned "Burst" there's another big difference the K3II is rated at up to 8.3 FPS (Buffer, 60 JPEG/23 Raw) vs the KP's 7 FPS (Buffer, 28 JPEG/8 Raw).
At first I was bummed about the lack of the pop up flash on the K3II, but frankly I've learned to live without it. The new KP has a built in stereo microphone, but surprisingly the K3II has a direct port for HDMI, and the new KP requires an adapter????? That doesn't make a whole lot of sense, and why would they go backward on the USB port from a 3.0 on the K3II to a 2.0 on the KP. Yes the new KP has a tilting screen, but it's smaller then the K3II (and I have trouble seeing it already).
In other backward moves, the KP no longer supports power zoom (on the K3II), only offers one card slot (not 2 like on the K3II), no built in GPS (on the K3II though I've yet to use it), and a change from all magnesium alloy on the K3II to a combination of magnesium and plastic. The addition of the WIFI on the KP is nice I really miss that, but I can't find any information on if the KP will support tethering. Something that isn't available on the K3II unless you put in a Flucard, and they can supposedly be a little flaky. Last but not least, the battery life went from 750 shots on the K3II to 450 on the KP.
So all in all, after reading more, I think I stay with the K3II for now.