Well, the exposure seems to be off on my K20D as with the ist-DS. I have it set to +0,5 to +1,0 all the time since the average correction I have to do in the RAW converter is about +0,7.
It is not just me, I talked to a number of Pentax users around me and they do the same.

As a replacement I am leaning towards the Sony A7-II at the moment but I am in no rush so I will wait another year probably.

What isn't helping the market share either is something I keep hearing from people who have a Pentax DSLR in my surroundings.
They all complain about the perceived lack of sharpness from the images taken by Pentax DSLR's compared to Canon/Nikon and I hear that both from people who are shooting RAW and who are shooting JPEG. Most of them have decent glass.
It is also something that I noticed together with the slight under exposing of images that both my ist-DS and my K20D do.
Both are not really issues but rather less in camera processing but I do get that 'new' players are not really impressed by the results.
I for one am looking for a replacement of my K20D but I do not know what to get, due to 'life' I have less time to process so I want good results right out of the camera without the need for processing for 80% of my images and that is simply not possible with my K20D. The results are great when taking the time to edit each and every image but I need a flexible camera that gives me both the option to give me RAW images so I can fiddle with them and images that are properly exposed and sharp right out of the camera.

I can't remember when I used the built-in flash of my K20D. I mainly use the 16-45 on it which is already to big and you get shadows from the flash.
A set of Cactus triggers solves the remote triggering of flashes jus nicely.

Same here, I haven't used anything more then a rocket blower and occasionally a Arctic Butterfly which is also a great tool.

Thanks for the insights!

Thanks for the replies, it pretty much confirms the ideas that had already.
Replacing the 50-200 won't be such a big deal I think.
So it will be time to start saving and trying to convince SWMBO that I need a new DSLR after 6 years

When I would be to buy a new K3 will I still be able to use my older lenses with it or will the sensor show the limits of these lenses?
I mainly use the Pentax DA16-45, DA50-200 and my Sigma 50-500.
I would like to upgrade to a newer body but I don't feel much like buying new glass to go with it.

During the vacation I wanted to make some nice shots of a sunset over a lake and to do this with my K20D the only way is to use bracketing and make 3 of 5 shots at different shutter speeds to prevent highlights from blowing out and shadows from being completely invisible.
The end results can be great when you do this but it is quite a bit of work.
When you use a half decent compact (my wife uses a Panasonic DMC-TZ20) it produces quite good results just out of the camera without bracketing. Is this because of the electronic shutter where it can "play" with individual parts of the sensor to get the correct exposure? I can't imagine that this little compact has a sensor with a higher dynamic range then the sensor in my K20D.

I don't mind if it was able to focus beyond infinity but with the 50-200 it can't move beyond that point even though the body tries to and so it fails to get a focus lock and refuses to take a picture unless I set it to manual focus.

I have an older DA50-200 which has loads of issues focussing around the infinity point. My K20D tries to focus beyond infinity especially when the contrast levels are not all that high. When I was on vacation I had to use it in manual focus most of the time.
Is this something which can be corrected in the focus adjustment setting for this lens?