Originally posted by Hidrieus I greatly value the internal flash for on the fly fill in. I want to have it for 24x36 sensor cameras too (Nikon D700/800). I was hoping for a return of it in the new APS-C flagship. So I will keep using my lovely K-5 and I will consider a used K-3. If you think this comment is out of place tell me and I will delete it.
I am sympathetic to your point of view, as I work in much the same way. If I should get a K-1 II FF body, I will do so mainly because of some excellent FF glass I have. If not for that, I probably would not consider getting into FF. The imaging from APS-C has become that good. I already have the really neat Pentax mini flash for the hot shoe, the AF201FG, which is small enough to be very pocketable, and has WR construction. It is a very good alternative when there is no built-in flash, and has some additional benefits. It has a tilt design for ceiling bounce, and it is more powerful than built-in flashes. It is not expensive. If the features and upgrades of the new K-3 III would be helpful for what you do, this might be a consideration.
I too bought a K-5 after the price came down, and found it to be a world of improved imaging capability over my K20D. Subsequently, after the K-3 came, I bought the upgraded K-5 IIs at a great closeout price, which offered improved AF with some lenses and no AA filter for better fine detail. I was able to increase sharpening levels up one more notch to +2 in the "Bright" setting with this sensor without negative effects, and then also implemented "Fine Sharpening" to take full advantage of not having the AA filter. I mirrored the same adjustments in the "Natural" setting. Although my favorite has become my KP during the last couple of years, I still like the results I get from my K-5 IIs very much along with its controls, so I still use it fairly often.