50-200mm oops no SR
Biggest issue with the 50-200 for me was the softer edges. If you look at Photozone you will see that a 50-200 that is within specs can't match a 55-300 that has a slight decentering issue (they had 2 different 50-200s sent by Pentax). Your photos don't refute that either. That tells me it would take an exceptional 50-200 to match a 55-300 that is just within specs. One reason I own the 55-300.
You are quite right mine is soft at the edges but unlike wider style landscape photography were that is important, I tend to use longer lenses to isolate one aspect of the scenery. Therefore the edges are often not so important. In fact I sometimes blur the edges in post, to emphasize the point of interest in the image. I know there are landscape images in the original post but that is because my chosen landscape lens is in for service to fix soft edges, of all things.