IMO, placement of the center of interest is important.
In the first version of the dog picture, the crop is somewhere between square and 4 x 5.
I try to crop to a standard aspect ratio for two reasons;first, ease in printing and framing and second, because people are used to seeing through standard windows and I don't want to call attention to the shape. That's not part of the picture for me.
Where the center of interest is in the frame and space around is important because viewers try to understand why that space is there. After all the photographer did it on purpose, what should the viewer understand out of it?
Here is a more extreme example.
The center of interest is her face and hands and there is a lot of space behind her and above. why? That space puts a question in the viewers' mind that has nothing to do with the point of the picture.
Now if the picture is cropped to a standard form, the space is removed and the centers of interest moved to a stronger position, then all of a sudden, the picture takes on a strength and interest it didn't have before.
The viewer doesn't think much about the hat and the muttens and snow become much more important.