Hi
I can,t see anything wrong with this image as far as sharpness is concerned.
I have this lens and I cannot find anything wrong with it. It produces stunning IQ.
Oh, wait a moment - I can find a problem with this lens, she is bloody heavy.
Different subject, don't know which of the available RAW converters you use, I use PS and their converter allows to recover highlights of images shot with the K-1 with breathtaking results. The washed out sky could be recovered like you would not believe your eyes. All you have to do is move the highlight slider to the left.
And most if not all RAW converters let you correct pin and barrel distortions, either automatically or manually.
Cheers