But maybe that's where I'm misunderstanding you, because maybe you only want to use "fair use" in the clear-cut areas, such as logos. But when it comes to an image of Dolly the Sheep, CC-ND is much more useful than fair use for the vast majority of reusers. Cropping is about the only useful modification I could see a reuser needing to make, and that's probably going to fall under fair use anyway.
Perhaps, but we aren't licensing Wikipedia images "cropping-only." If we publish an image of Dolly under the GFDL, we have claimed that anyone can take that image and do /anything/ to it, including make a picture of her kicking down the World Trade Center with George Bush cheering her on.
There are no provisions in the license we're using for specifying that some changes are okay and others aren't.
I once again refer everyone to my correspondence with HMSO. Many lawyer-wannabes on this list are happy to advise us to ignore the clearly-stated position of Her Majesty's Government. Of course, /they/ aren't the ones who will have to defend their opinions in court....