post processing - How to correct perspective and geometric distortion?

This is the original photograph I took with a Canon 6D and focal length 80mm (desaturated):

I wanted the building to use up more space, so I cropped it:

Because of the tilt of the off-center crop, I corrected the perspective distortion using a software tool:

Now it looked really unnatural, so I tried correcting the perspective distortion from the original not-cropped photo:

This looks better, but still unnatural.

Finally, I am wondering what is the correct or a good way to photograph a building like this?

I think the original photo is still the best, although I am not quiet happy with it, but all the corrected images seem to be unnatural, and the cropping obviously doesn't look good if it is off-center.

Is there an option to improve the photo in post processing?

Answer

What I see there is that the software managed to do affine transformation (change the pitch of the camera), but forgot about lens distortion. Ofcourse, to do a full blown perpective recomputation you need a 3D model of the scene, as affine transformation only models the scene as a plane. So you get to choose, if you want the front wall straight or the back wall.

Here I did a quick pitch, a bit of roll, and also lens-de-distortion. I made the front wall parallel.

If you want to avoid having to do it in post, you need a shift/tilt lens, or a very wide angle lens and place the building in the upper half, keeping the camera level.