I LOVE cropping - it is an important tool in my image making.
I have never understood why - just because someone many many years ago decided the negative should be 24x36 / 6x6/6x7/..you get it - I should let that decide how my images should look?
what if I want a round camera? - a panoramic format of my choosing? rounded corners?
It's like being a painter and be told ONLY to stick to certain formats....
In a speech I heard many years ago the speaker stated: An image only has one format and size!: The RIGHT one...
Only the real artists instinctively know how the format and size their image must have to be "perfect".. (he was talking mostly about painters).
At least we have the option to experiment with the size...
I'll be provocative and say: NOT cropping at all, is just being lazy...

(allthough I find it amazing when a non cropped image really sing)