From my point of view the crop settings of images should be handled at file level and on file reference level. We have some customers with quit big TYPO3 instances, and they use defined crop variants all over the whole page. Every time the add a file reference the editor has to set the same crop variants again and again and again. If the (default) crop variant could be set at file level and be overwritten at file reference level this would be a huge advantage.
I’m aware that this may is not a simple topic since custom crop variants on element level are possible. I just want to share my thoughts and may start a discussion.