I think it is a question of aesthetics. I bought a Sunbonnet pattern that was a rectangle. I didn't want it to be a rectangle, so I changed the number of columns & rows and added some extras to the quilt to make it the shape I enjoy.
Is my niece square-shaped? No! But she isn't rectangle-shaped either, so I figure it's a wash.
If you like a particular pattern, but prefer quilts that are long & narrow, why not just add a few more rows of blocks &/or take away some columns of blocks until it is the approximate size you'd like?
